Пример #1
0
        protected void Page_Load(object sender, EventArgs e)
        {
            //every time the page is processed (submitted to the
            //    web server) this method is the FIRST event
            //    that is processed that you can easily see and
            //    interaction with.

            //this is a great place to do common code that is
            //    required on each process of the page
            //Example: empty out old messages

            //every control on your web form is a class instance
            //every control has an ID property
            //every control must have a unique name
            //the ID value is used to reference the control in
            //   your code behind
            //since controls are instances of a class, all rules
            //   of OOP apply
            MessageLabel.Text = "";

            //the web page has a flag that can be checked to see
            //   if the web page is posting back
            if (!Page.IsPostBack)
            {
                //if the page is not PostBack, it means that this
                //    is the first time the page has been displayed
                //you can do page initialization by testing the
                //    IsPostBack
                //Create a List<T> where T is a class that has
                //    2 columns: a value and a text display
                List <DDLData> DataCollection = new List <DDLData>();
                DataCollection.Add(new DDLData(1, "COMP1008"));
                DataCollection.Add(new DDLData(3, "DMIT1508"));
                DataCollection.Add(new DDLData(4, "DMIT2018"));
                DataCollection.Add(new DDLData(2, "CPSC1517"));

                //sorting a List<T>
                // (x,y) are placeholders for 2 records at any given time in the sort
                // => (lamda symbol) is part of the delegate syntax, read as "do the following"
                // comparing x to y is ascending
                // comparing y to x is descendinng
                DataCollection.Sort((x, y) => x.displayField.CompareTo(y.displayField));

                //place the data into the dropdownlist control
                //a) assign the data collection to the "list" control
                CollectionList.DataSource = DataCollection;

                //b) this step is required for specific "list" controls
                //indicate which data value is to be assigned to the Value field and the Display text field
                //there are different styles in assigning this information
                CollectionList.DataValueField = "valueField";
                CollectionList.DataTextField  = nameof(DDLData.displayField); //don's preference

                //c)bind your data to the actual control
                CollectionList.DataBind();

                //d)OPTIONALLY you can place a prompt line on your control
                CollectionList.Items.Insert(0, new ListItem("select....", "0"));
            }
        }
        protected void Page_Load(object sender, EventArgs e)
        {
            //this method will execute on EACH and EVERY post back
            //to this page.
            //this method will execute on the first display of this page
            //To determine if the page is new or postback use IsPostBack property

            //this method is often used as a general method to reset
            //fields or controls at the start of the page processing
            //The label MessageLabel is used to display messages to the user
            //Old messages should be remove from this control on each pass

            //How does one reference a control on the .aspx form
            //To reference a form control, use the control ID name
            //EACH control is an object. THEREFORE alter a PROPERTY value.
            MessageLabel.Text = "";

            //Determine if this is the first display of the page
            //  and if so, load data into the dropdownlist
            if (!Page.IsPostBack)
            {
                //Create an instance of List<T> for my "fake database" data
                DataCollection = new List <DDLClass>();

                //add data to the collection, one entry at a time
                DataCollection.Add(new DDLClass(1, "COMP1008"));
                DataCollection.Add(new DDLClass(2, "DMIT1508"));
                DataCollection.Add(new DDLClass(3, "CPSC1517"));
                DataCollection.Add(new DDLClass(4, "DMIT2018"));

                //usually lists are sorted
                //The List<T> has a .Sort() behaviour (method)
                //(x,y) represents any two entries in the data collection at any point in time
                // the lamda symbol => basically means "do the following"
                //.CompareTo() is a method that will compare to items and return the result
                //   of comparing two items. The result is interpreted by the Sort() to
                //   to determine if the order needs to be changed.
                // x vs y is ascending
                // y vs x is descending
                DataCollection.Sort((x, y) => x.DisplayField.CompareTo(y.DisplayField));

                //place the collection into the dropdownlist
                //a) assign the collection to the control (ID=CollectionList)
                CollectionList.DataSource = DataCollection;

                //b)assign the value and display portions of the dropdownlist
                //     to specify properties of the data class
                CollectionList.DataTextField  = nameof(DDLClass.DisplayField);
                CollectionList.DataValueField = nameof(DDLClass.ValueField);

                //c)Bind the data to the collection (physical attachment)
                CollectionList.DataBind();

                //d)You may wish to add a prompt line at the beginning of the
                //     list of data within the dropdownlist
                CollectionList.Items.Insert(0, "select...");
            }
        }
Пример #3
0
        protected void Page_Load(object sender, EventArgs e)
        {
            //this method executes BEFORE any event method on EACH processing of this web page
            //this is a great place to do common code that is required on EACH process of the page
            //Example: empty out old messages
            Messagelabel.Text = "";

            //this is an excellent place to do page initilization of controls for the first time
            //checking the first time  for the page uses the post back flag
            //IsPostBack is a boolean value (true or false)
            if (!Page.IsPostBack)
            {
                //if the page if not PostBack, it meanss that this if the first time the page has been displayed
                //you can do page initalization

                //create a collection of  instances (class objects) that will be used to load the dropdownlist
                //this will simulate the loading control as if the data can from a databases table
                //each instance would represent a record on the database dataset
                //to acomplish this simulation
                List <DDLData> DDLCollection = new List <DDLData>();
                DDLCollection.Add(new DDLData(1, "COMP1008"));
                DDLCollection.Add(new DDLData(3, "DMIT1508"));
                DDLCollection.Add(new DDLData(4, "DMIT2018"));
                DDLCollection.Add(new DDLData(2, "CPSC1517"));

                //place the data into the dropdownlist control
                //4 steps to this process

                //1) assign the data collection to the contorl
                CollectionList.DataSource = DDLCollection;

                //2) in this step, you will assign the value that will be displayed to the user and the value that will be associated
                //and return from the control when the user picks a particular selection
                //in the <select> control, this data was setup using the <option>
                //      <option value = "xxx"> display string </option>

                //2 styles in setting up the control values
                //A) a physical string of the field name
                CollectionList.DataValueField = "ValueID";
                //B) OOP style coding
                CollectionList.DataTextField = nameof(DDLData.DisplayText);

                //3) bind your data source to your control
                CollectionList.DataBind();

                //4) optional is to add a prompt list to your dropdownlist
                CollectionList.Items.Insert(0, new ListItem("select...", "0"));

                //sorting a List<T>
                //(x,y) are place holder representing any 2 records at any given time druing the sort
                //=> (lamda symbol) is part of the delegate syntax, I suggest that you read this symbol as "do the following"
                //comparing x to y is ascending
                //comparing y to x is descending

                DDLCollection.Sort((x, y) => x.DisplayText.CompareTo(y.DisplayText));
            }
        }
Пример #4
0
        protected void Page_Load(object sender, EventArgs e)
        {
            //this method is excuted automatically on each and every pass of the page (~kinda like IsPost)
            //this method is executed BEFORE any event method on this page

            //clear any old messages
            OutputMessage.Text = "";

            //this method is an excellant place to do page initialization
            //you can test to post back on the page (IsPost)
            // by checking Page.IsPostBack property

            if (!Page.IsPostBack)
            {
                //the first time the page is processed

                //create an intance of out list<t>
                DataCollection = new List <DDLClass>();

                //load the collection with a series of DDLCLASS instances
                //create the instances using the greedy constuctor

                DataCollection.Add(new DDLClass(1, "COMP1008"));
                DataCollection.Add(new DDLClass(2, "CPSC1517"));
                DataCollection.Add(new DDLClass(3, "DMIT2018"));
                DataCollection.Add(new DDLClass(4, "DMIT1508"));

                //use the list<t> method called .Sort to sort the contents of the list
                // (x,y) the x and y represent two instances at any time in your collection
                // x.field compared to y.field (ascending)
                // y.field compared to x.field (decending)
                DataCollection.Sort((x, y) => x.DisplayField.CompareTo(y.DisplayField));

                //load the datacollection to the asp control you are interested in
                // we are using the DropDownList
                //a) assign you DataCollection to the control
                CollectionList.DataSource = DataCollection;

                //b) setup any necessary properties on your ASP control that are required to work
                //the dropdown list will generate the html select tag code
                // thus we need two properties to be set
                // i)the value property DataValueField
                // ii)the display property DataTextField
                // the properties are set up by assigning the dataCollection field name to teh control property
                CollectionList.DataValueField = "ValueField";
                CollectionList.DataTextField  = nameof(DDLClass.DisplayField);

                // C) BIND your data to the control
                CollectionList.DataBind();

                // what about prompts?
                // manually place a line item at the beginning of your control
                CollectionList.Items.Insert(0, "select...");
            }
        }
        protected void Page_Load(object sender, EventArgs e)
        {
            //this event method is executed EACH and EVERY time
            // this page is processed
            //this event method is executed BEFORE ANY EVENT method is processed

            //clear out all old message
            OutputMessage.Text = "";

            //this page is an excellent place to do page initialization
            //  of your controls.
            //there is a property to test for post back of your
            //  page called Page.IsPostBack (Razor: IsPost)
            if (!Page.IsPostBack)
            {
                //do 1st page initialization processing

                //create an instance of the data collection list
                DataCollection = new List <DDLClass>();

                //load the data collection with dummy data
                //normally this data would come from your database
                DataCollection.Add(new DDLClass(1, "COMP1008"));
                DataCollection.Add(new DDLClass(2, "CPSC1517"));
                DataCollection.Add(new DDLClass(3, "DMIT2018"));
                DataCollection.Add(new DDLClass(4, "DMIT1508"));

                //to sort a List<T> use the method .Sort()
                //(x,y) x and y represent any two instances in your list at any time
                //x.field compared to y.field : ascending
                //y.field compared to x.field : descending
                DataCollection.Sort((x, y) => x.DisplayField.CompareTo(y.DisplayField));

                //setup the dropdownlist (radiobuttonlist, checkboxlist)
                //a) assign your data to the control
                CollectionList.DataSource = DataCollection;

                //b) assign the data list field names to
                //      the appropriate control properties
                //  i) .DataValueField this is the value of the select option
                // ii) .DataTextField this is the display of the select option
                CollectionList.DataValueField = "ValueField";
                CollectionList.DataTextField  = nameof(DDLClass.DisplayField);

                //c) phyiscally bind the data to the control for show
                CollectionList.DataBind();

                //what about a prompt?
                //one can add a prompt to the start of the BOUND control list
                //one will use the index 0 to position the prompt
                CollectionList.Items.Insert(0, "select ....");
            }
        }
        protected void Page_Load(object sender, EventArgs e)
        {
            //This method is executed automatically on EACH and EVERY pass of the page.
            //This method is executed BEFORE ANY EVENT method on this page.


            //clear any old messages
            OutputMessage.Text = "";
            //This method is an excellent place to do page initialization.
            //You can test the postback of the page (Razor IsPost) by checking the Page.IsPostBack property.
            if (!Page.IsPostBack)
            {
                //The first time the page is proccessed.

                //Create an instance of the list of T.
                DataCollection = new List <DDLClass>();

                //Load the collection with a series of DDLClass instances. Create the instances using the greedy constructor.
                DataCollection.Add(new DDLClass(1, "COMP1008"));
                DataCollection.Add(new DDLClass(2, "CPSC1517"));
                DataCollection.Add(new DDLClass(3, "DMIT2018"));
                DataCollection.Add(new DDLClass(4, "DMIT1508"));
                //When we use db's, this is the only thing that will be replaced.

                //Use the List<T> method called .Sort to sort the contents of the list.
                //(x,y) the x and y represent any 2 instances at any time in your collection.
                //x.field compared to y.field (ascending)
                //y.field compared to x.field (descending)
                DataCollection.Sort((x, y) => x.DisplayField.CompareTo(y.DisplayField));
                //=> is a Lambda expression, don't mix it up with >=!
                //=> Means for X and Y, /do the following/, then specify what you want done.

                //Load your data collection to the ASP control you are interested in: DropDownList
                //Could also be done to a radio button list dynamically.
                //A) Assign your data collection to the control.
                CollectionList.DataSource = DataCollection;

                //B) Setup any neccessary properties on your ASP control that are required to properly work.
                //The dropdownlist will generate the HTML select tag code. Thus we need 2 properties to be set.
                //i) Value property (DataValueField)
                //ii) Display property (DataTextField)
                //The properties are set up by assigning the data collection field name to the control property.
                CollectionList.DataValueField = "ValueField";
                CollectionList.DataTextField  = nameof(DDLClass.DisplayField); //A way to do it without hardcoding the value.

                //C) Bind your data to the control.
                CollectionList.DataBind();

                //What about prompts? Manually place a line item at the beginning of your control.
                CollectionList.Items.Insert(0, "select ...");
            }
        }
        protected void Page_Load(object sender, EventArgs e)
        {
            //This method will execute on each and every Postback to this page.
            //This menthod will execute on the first display of this page
            //To determine if the page is new or postback, use PostBack Property.
            //This method is often used as a general method to reset fields or controls at the start of the page processing.
            //E.g. The label MessageLabel is used to display messages to the user. Old messages should be removed from this control on each pass

            // How does one reference a control on the .aspx form?
            //To reference a form control, use the control ID name
            //EACH CONTROL IS AN OBJECT. Therefore, ALTER A PROPERTY VALUE
            MessageLabel.Text = "";

            //Determine if this is the first display of the page, and if so, load data into the dropdownlist
            if (!Page.IsPostBack)
            {
                //Create an instance of List<T> for my "Fake Database Data"
                DataCollection = new List <DDLClass>();

                //Add data to the collection, one entry at a time
                DataCollection.Add(new DDLClass(1, "COMP1008"));
                DataCollection.Add(new DDLClass(3, "DMIT1508"));
                DataCollection.Add(new DDLClass(2, "CPSC1517"));
                DataCollection.Add(new DDLClass(4, "DMIT2018"));

                //usually lists are sorted
                //The List<T> has a .Sort() behavior (method)
                //(x,y) represent any two entries in the data collection at any point in time
                //The landa symbol "=>" :  basically means do the following
                //.CompareTo() : is a method that would compare 2 items and return the result of the comparison.
                //The result is interpreted by the Sort() to determine if the order needs to be changed.
                // x vs y is ascending
                // y vs x is descending

                DataCollection.Sort((x, y) => x.DisplayField.CompareTo(y.DisplayField));

                //Place the collection into the dropdown list
                //a) assign the collection to the control (CollectionList)
                CollectionList.DataSource = DataCollection;

                //b) assign the value and display portions of the dropdownlist to specific properties of the data class
                CollectionList.DataTextField  = nameof(DDLClass.DisplayField);
                CollectionList.DataValueField = nameof(DDLClass.ValueField);

                //c) Bind the data to the collection (physical attachment)
                CollectionList.DataBind();

                //d) you may wish to add a prompt line at the beginning of the list of data within the dropdownlist
                CollectionList.Items.Insert(0, "Select...");
            }
        }
Пример #8
0
        protected void Page_Load(object sender, EventArgs e)
        {
            //Page_Load executes EACH AND EVERY time there is a posting
            //  to this page
            //Page_Load is executed before any submit events

            //this method is an excellent place to do form initialization
            //you can test your postings using Page.IsPostBack
            //IsPostBack is the same item as IsPost in our Razor forms

            if (!Page.IsPostBack)
            {
                //this code will be executed only on the first pass
                //  to this page

                //create an instance for the static data collection
                DataCollection = new List <DDLClass>();

                //Add instances to this collection using the DDLClass
                //  greedy constructor
                DataCollection.Add(new DDLClass(1, "COMP1008"));
                DataCollection.Add(new DDLClass(2, "CPSC1517"));
                DataCollection.Add(new DDLClass(3, "DMIT2018"));
                DataCollection.Add(new DDLClass(4, "DMIT1508"));

                //sorting a list<t>
                //use the .Sort() method
                //(x,y) this represents any two items in your list
                //compare x.Field to y.Field, ascending order
                //compare y.Field to x.Field, descending order
                DataCollection.Sort((x, y) => x.DisplayField.CompareTo(y.DisplayField));

                //put the data collection into the drop down list
                //a) assign the collection to the controls dataSource
                CollectionList.DataSource = DataCollection;

                //b) assign the field names to the properties of the
                //  drop down list for data association
                //DataValueField represents the value of the item
                //DataTextField represents the display of the line item
                CollectionList.DataValueField = "ValueField";
                CollectionList.DataTextField  = nameof(DDLClass.DisplayField);

                //c) bind the data to the web control
                CollectionList.DataBind();

                //can one put a prompt on the drop down list control?
                //  short answer: yes
                CollectionList.Items.Insert(0, "select...");
            }
        }
Пример #9
0
        protected void Page_Load(object sender, EventArgs e)
        {
            //if you need to reset fields on each pass (process) of the page
            // you can do it here
            //page initialization can be done here under the IsPostBack flag

            //the ID= attribute on your control is the name that is use in
            //  your code to reference the control
            //the ID= name is unique to the form
            //each control is an object and behaves as an object
            MessageLabel.Text = "";

            //the test for posting a form back to the web server is IsPostBack
            if (!Page.IsPostBack)
            {
                //load the DropDownList (DDL) only on the first pass of the page
                //In this example a locally create List<T> will act
                //   as the data source for the DDL
                DataCollection = new List <DDLClass>();

                //add instances to the list
                DataCollection.Add(new DDLClass(1, "COMP1008"));
                DataCollection.Add(new DDLClass(2, "DMIT1508"));
                DataCollection.Add(new DDLClass(3, "CPSC1517"));
                DataCollection.Add(new DDLClass(4, "DMIT2018"));

                //place the data in the DDL in alphabetic order (ascending)
                //(x,y) represent any two rows in the collection DataCollection
                //Compare x.DisplayField to y.DisplayField, ascending
                //Compare y.DisplayField to x.DisplayField, descending
                DataCollection.Sort((x, y) => x.DisplayField.CompareTo(y.DisplayField));

                //to place a collection into the DDL control we need to do 4 steps
                //a) assign the collection to the control's DataSource property
                CollectionList.DataSource = DataCollection;

                //b) assign field names to the properties DataTextField and DataValueField
                //the DataTextField contents the data seen by the user
                //the DataValueField is the data returned by the control on access*
                CollectionList.DataTextField  = "DisplayField";
                CollectionList.DataValueField = "ValueField";

                //c) Bind the information and data to your control
                CollectionList.DataBind();

                //d) optional, assign a prompt to your control
                //such that it appears before the data
                CollectionList.Items.Insert(0, "select....");
            }
        }
Пример #10
0
        protected void Page_Load(object sender, EventArgs e)
        {
            //page load executes each and every time there is a posting to this page
            //page load is executed before any submit events

            //this method is and exelent place to do form initialization
            // you can test your postings using Page.IsPostBack

            //page.IsPostBack is the same as IsPost in our razor
            if (!Page.IsPostBack)
            {
                //this code will be executed only on the first pass to this page

                //create an instance for the static data collection
                DataCollection = new List <DDLClass>();

                //Add instances to this collection using the DDL gready constructor
                DataCollection.Add(new DDLClass(1, "COMP1008"));
                DataCollection.Add(new DDLClass(2, "CPSC1517"));
                DataCollection.Add(new DDLClass(3, "DMIT2018"));
                DataCollection.Add(new DDLClass(4, "DMIT1508"));
                //Sorting a list of <T>
                //using the .Sort() method
                //(x,y) this represents any two items in your list
                //Compare x.Field to y.Field; acending
                //Compare y.field to x.field; decending
                DataCollection.Sort((x, y) => x.DisplayField.CompareTo(y.DisplayField));

                //put the data collection into the dropdown list
                //a) assign the collection to the controls DataSource
                CollectionList.DataSource = DataCollection;

                //b) assign the field names to the properties of the drop down list for data association
                //data value field represents the value of the item
                //data text value represents the display value of the line item
                CollectionList.DataValueField = "ValueField";
                CollectionList.DataTextField  = "DisplayField";
                //CollectionList.DataTextField = nameof(DDLClass.DisplayField);

                //c) bind the data to the web control
                //NOTE: this statment is NOT required in a windows form application
                CollectionList.DataBind();

                //Can one put a promt on their drop down list control
                //yes
                CollectionList.Items.Insert(0, "select ...");
            }
        }
Пример #11
0
        protected void Page_Load(object sender, EventArgs e)
        {
            //this method is executed each and every time you process this webpage
            //this method executes before the event method
            //this method is an excellent place to do initial form setup
            //this method is an excellent place to change any control that may need to be done for the same action under all events

            //example - clearing old messages
            // a control is referenced in the code-behind by using its ID="controlname"
            //Control names are global to all events

            MessageLabel.Text = "";

            //Assume you wish to do page intialization of some type but only one when the page is first loaded
            if (!Page.IsPostBack)
            {
                DataCollection = new List <DDLClass>();
                //load collection using greedy constructor and load to the list
                DataCollection.Add(new DDLClass(1, "COMP1008"));
                DataCollection.Add(new DDLClass(2, "CPSC1517"));
                DataCollection.Add(new DDLClass(3, "DMIT1508"));
                DataCollection.Add(new DDLClass(4, "DMIT2018"));


                //List<T> can be sorted using .Sort(Delegate) Depending on your method, the delegate will be different.
                //syntax for delegate
                // (x,y) => x.PropertyName.CompareTo(y.PropertyName)
                DataCollection.Sort((x, y) => x.DisplayField.CompareTo(y.DisplayField));

                //attach the data to the dropdownlist control
                //attach data
                CollectionList.DataSource = DataCollection;

                //assign the display text property to the ddl control - there are a couple of ways
                //way THE FIRST
                CollectionList.DataTextField = "DisplayField";

                //WAY THE SECOND
                //assign the value data property to the ddl control
                CollectionList.DataValueField = nameof(DDLClass.ValueField);

                //then do the databind thing
                CollectionList.DataBind();

                //optionally add a prompt line
                CollectionList.Items.Insert(0, "Select ...");
            }
        }
Пример #12
0
        protected void Page_Load(object sender, EventArgs e)
        {
            //Page_Load executes each and every time there is a posting
            //  to this page.
            //Page_Load is executed before any submit events

            //this method is an excellent place to do form initilizition
            //You can Test your postings using Page.IsPostBack
            //IsPostBack is the same item as IsPost in Razor Forms

            if (!Page.IsPostBack)
            {
                //this code will be executed only on the first pass
                // to this page

                //create an instance for the static data collection
                DataCollection = new List <DDLClass>();
                //add instances to this collection using the DDLClass
                //  greedy constructor
                DataCollection.Add(new DDLClass(1, "COMP1008"));
                DataCollection.Add(new DDLClass(2, "CPSC1517"));
                DataCollection.Add(new DDLClass(3, "DMIT2018"));
                DataCollection.Add(new DDLClass(4, "DMIT1508"));
                //sorting a List<T>
                //use the .Sort() method
                //(x,y) this represents any two items in your list
                //compare x.Field to y.Field; ascending
                //Compare y.Field to x.Field; descending
                //=> lambda symbol. Think of it as Do the Following
                DataCollection.Sort((x, y) => x.DisplayField.CompareTo(y.DisplayField));
                //Put the data collection into the dropdownlist
                //a) assign the collection to the controls DataSource
                CollectionList.DataSource = DataCollection;
                //b) assign the field names to the properties of the
                //  dropdownlist for data association
                //DataValueField represents the value of the item
                //DataTextField represents the display of the line item
                CollectionList.DataValueField = "ValueField";
                CollectionList.DataTextField  = nameof(DDLClass.DisplayField);
                //c) bind the data to the web control
                //NOTE: This Statement is NOT required in a Windows Form Application
                CollectionList.DataBind();
                //Can one put a prompt on their dropdownlist control?
                //  Obvs, Yes.
                CollectionList.Items.Insert(0, "Select...");
            }
        }
        protected void Page_Load(object sender, EventArgs e)
        {
            // load empty feilds on first page refresh
            Message.Text = "";

            //------------------DROP DOWN LIST------------------------

            //the web page has a flag that can be checked to see
            //   if the web page is posting back
            if (!Page.IsPostBack)
            {
                //if the page is not PostBack, it means that this
                //    is the first time the page has been displayed
                //you can do page initialization by testing the
                //    IsPostBack
                // LIST is a bunch of the same classes
                //Create a List<DDLdata> where T is a class that has
                //    2 columns: a value and a text display

                List <DDLData> ReviewStars = new List <DDLData>();

                // adding values to the list
                ReviewStars.Add(new DDLData(1, "1 star"));
                ReviewStars.Add(new DDLData(2, "2 stars"));
                ReviewStars.Add(new DDLData(3, "3 stars"));
                ReviewStars.Add(new DDLData(4, "4 stars"));
                ReviewStars.Add(new DDLData(5, "5 stars"));

                // SORT
                ReviewStars.Sort((x, y) => x.displayField.CompareTo(y.displayField));

                // grab form id  and place Review list into drop down list
                CollectionList.DataSource = ReviewStars;

                // if there is a value and text feild do this
                CollectionList.DataValueField = "valueField";
                CollectionList.DataTextField  = nameof(DDLData.displayField);

                //bind your data
                CollectionList.DataBind();

                // add in an insert
                CollectionList.Items.Insert(0, new ListItem("select...", "0"));
            }
        }
        protected void Page_Load(object sender, EventArgs e)
        {
            OutputMessage.Text = "";
            //this event method is executed EACH and EVERY time this page is processed
            //this event method is executed BEFORE ANY EVENT method is processed

            //this page is an excellent place to do page initialization of your controls
            //there is a property to test for post back of your page called Page.IsPostBack (Razor: IsPost)
            if (!Page.IsPostBack)
            {
                //do 1st page initialization processing
                //create an intence of the Data colletion list
                DataCollection = new List <DDLClass>();

                //load the data collection with dummy data, normally this data would com from your database
                DataCollection.Add(new DDLClass(1, "Comp1008"));
                DataCollection.Add(new DDLClass(2, "Cpsc1517"));
                DataCollection.Add(new DDLClass(3, "Dmit2018"));
                DataCollection.Add(new DDLClass(4, "Dmit1508"));

                //to sort List<T> use the method .Sort()
                //(x,y) x and y represent any two instances in your list at any time.
                // x.firld compared to y.field : ascending
                // y.field compared to x.field : desending
                DataCollection.Sort((x, y) => x.DisplayField.CompareTo(y.DisplayField));

                //setup the dropdown list

                //a, assign your data to the control
                CollectionList.DataSource = DataCollection;
                //b, assign the data list field names to the approriate control properties
                //  i), .DatavalueField this is the value of the selection
                //  ii) .DataTextFiled this is the display of the selection optio
                CollectionList.DataValueField = "ValueField";
                CollectionList.DataTextField  = nameof(DDLClass.DisplayField);
                //bind the data to the control for show
                CollectionList.DataBind();

                //promt
                //one can adda  prompt to the start of the BOUND controllist
                //one will use the index 0 to position the prompt
                CollectionList.Items.Insert(0, "plese select");
            }
        }
Пример #15
0
        protected void Page_Load(object sender, EventArgs e)
        {
            //Page_Load executes EACH AND EVERY TIME there is a posting to this page
            //Page_Load is executed BEFORE any submit events

            //this method is an excellent place to do form initialization. you can test your postings using Page.IsPostBack
            //IsPostBack == IsPost() in Razor forms

            //only executed on first pass, not ispost
            //create an instance for the static data collection
            if (!Page.IsPostBack)
            {
                DataCollection = new List <DDLClass>
                {
                    //Add instances to this collection using the DDLClass greedy constructor
                    new DDLClass(1, "COMP1008"),
                    new DDLClass(2, "CPSC1517"),
                    new DDLClass(3, "DMIT2018"),
                    new DDLClass(4, "DMIT1508")
                };

                //sorting a List<T>
                //use the .Sort() method
                //(x,y) this represents any 2 items in your list
                //compare x.Field to y.Field; ascending
                //compare y.Field to x.Field; descending
                DataCollection.Sort((x, y) => x.DisplayField.CompareTo(y.DisplayField));

                //put the data collection into the dropdownlist (DDL)
                //A) assign the collection to the controls DataSource
                CollectionList.DataSource = DataCollection;
                //B) assign the field names to the properties of the DDL for data association
                //DataValueField represents the value of the item
                //DataTextField represents the display of the line item
                CollectionList.DataValueField = "ValueField";
                CollectionList.DataTextField  = "DisplayField";
                //OR  CollectionList.DataTextField = nameof(DDLCLass.DisplayField);
                //C) bind the data to the web control
                //NOTE: this statement is NOT required in a Windows Form Application
                CollectionList.DataBind();
                //you can put a prompt on their dropdownlist control
                CollectionList.Items.Insert(0, "Select ...");
            }//closes !Page.IsPostBack
        }
        protected void Page_Load(object sender, EventArgs e)
        {
            //Page_Load executes each and every time there is a posting to this page
            //it is executed before any submit events
            //This method is an exelent place to do form initialization
            //you can test your postings using Page.IsPostBack
            //IsPostBack is the same item as IsPost from the Razor forms
            if (!Page.IsPostBack)
            {
                //create an instance for the static data collection
                DataCollection = new List <DDLClass>();

                //Add instance to this collection using the DDLClass greedy constructor
                DataCollection.Add(new DDLClass(1, "COMP1008"));
                DataCollection.Add(new DDLClass(2, "CPSC1517"));
                DataCollection.Add(new DDLClass(3, "DMIT2018"));
                DataCollection.Add(new DDLClass(4, "DMIT1508"));

                //sorting a List<T>
                //use the .sort()method
                //(x,y) represents any 2 items in the list
                //compare x.field to y.field; ascending
                //if we compare y.field to x.field; descending
                DataCollection.Sort((x, y) => x.DisplayField.CompareTo(y.DisplayField));

                //put the data Collection into the drop down list
                //a)assign the collection to the controls data source
                CollectionList.DataSource = DataCollection;

                //b) assign the field names through the properties of the drop down list for data association
                //DateValueField rpresents the value fot he item
                //DataTextField represents the display of the line item
                CollectionList.DataValueField = "ValueField";
                CollectionList.DataTextField  = nameof(DDLClass.DisplayField);

                //c)bind the data to the web control
                //NOTE: This statement is not required in a windows form app
                CollectionList.DataBind();

                //can one put a prompt on their drowdownlist control
                //yes
                CollectionList.Items.Insert(0, "select ...");
            }
        }
        //this method is executed every time the page is processed
        //this event method is executed before any event method is processed
        //this is a good place to do initialization of your controls
        //there is a property to test for postback of your page
        protected void Page_Load(object sender, EventArgs e)
        {
            //clear old messages
            OutputMessage.Text = "";

            if (!Page.IsPostBack)
            {
                //page init
                DataCollection = new List <DDLClass>();

                //load the data collection with dummy data
                //normally this data would come from your database
                DataCollection.Add(new DDLClass(1, "COMP1008"));
                DataCollection.Add(new DDLClass(2, "CPSC1517"));
                DataCollection.Add(new DDLClass(3, "DMIT2018"));
                DataCollection.Add(new DDLClass(4, "DMIT1508"));

                //sort arraylist
                //(x,y)
                //x.field compared to y.field = ascending
                //y.field compared to x.field = decending
                DataCollection.Sort((x, y) => x.DisplayField.CompareTo(y.DisplayField));

                //setup the dropdown list (works for radiobutton or dropdown lists as well)
                //a) assign your data to the control
                CollectionList.DataSource = DataCollection;

                //b) assign the data list field names to the appropriate control properties
                //  i) .DataValueField this is the value of the select option
                //  ii) .DataTextField this is the display of the select option
                CollectionList.DataValueField = "ValueField";
                CollectionList.DataTextField  = nameof(DDLClass.DisplayField);

                //c) physically bind the data to the control for show
                CollectionList.DataBind();

                //what about a prompt?
                //one can add a prompt to the start of the BOUND control list
                //one will use the index 0 to position the prompt
                CollectionList.Items.Insert(0, "select...");
            }
        }
Пример #18
0
        protected void Page_Load(object sender, EventArgs e)
        {
            //Every time the page is processed (submitted to the web server) this method is the FIRST event that is processed that you can easily see and interact with

            //This is a great place to do common code that is required on each process of the page
            //Example: empty out old messages

            //Every Control on your web form is a class instance
            //Every control has an ID property
            //Every control must have a unique name
            //The ID value is used to reference the control in your code behind
            //Since controls are instances of a class, all rules of OOP apply
            MessageLabel.Text = ""; //is the ID of the field that is shown on the bottom of the page (our output field)


            //The web page has a flag that can be checked to see if the web page is posting back
            if (!Page.IsPostBack)
            {
                //If the page is NOT PostBack, it means that this is the first time the page has been displayed
                //You can do page initialization by testing the IsPostBack
                //Create a List<T> where T is a class that has 2 columns: a value and a text display
                //In die Klammer kommt die Type of objects (wo jetzt das T steht --> zb int oder float)
                //Das T ist der Type of object, in diesem Fall ist der Type of object eine class die wir programmmiert haben ist oder build in ist

                //int x
                //List DataCollection
                List <DDLData> DataCollection = new List <DDLData>(); //DataCollection is the name of the property in the Class Page called "DDL Data
                DataCollection.Add(new DDLData(1, "COMP1008"));       // new DDLData --> ist ein Object createn
                DataCollection.Add(new DDLData(3, "DMIT1508"));
                DataCollection.Add(new DDLData(4, "DMIT2018"));
                DataCollection.Add(new DDLData(2, "CPSC1517"));
                //Wir brauchen hierfuer einen Constructor weil wenn wir eine instance von ner object createn dann ist die Zahl und der Name required
                //Wenn wir nix eingeben wuerden wuerde der leere constructor geurfen (nix in der Klammer)


                //Sorting a List<T>
                //(x,y) are placeholders for 2 records at any given time in the sort
                // => (lamda symbol) is part of the delegate syntax, read as "do the following"
                //Comparing x to y is ascending
                //Comparing y to x is descending
                DataCollection.Sort((x, y) => x.displayField.CompareTo(y.displayField));


                //Place the data into the dropdownlist control
                //a) assign the data collection to the "list" Control
                CollectionList.DataSource = DataCollection;   //CollectionList is the ID of the DROPDOWN and DataCollection of the List we created


                //b) This step is required for specific "list" controls
                //Indicate which data value is to be assigned to the Value field and the Display text field
                //There are different styles in assigning this information
                CollectionList.DataValueField = "valueField";
                CollectionList.DataTextField  = nameof(DDLData.displayField); //don's preference
                //Other controls that handle lists we don't need B; we only need A and C

                //c)Bind your data to the actual control
                CollectionList.DataBind(); //CollectionList is the name of the Dropdown

                //d)OPTIONALLY you can place a prompt line on your control
                CollectionList.Items.Insert(0, new ListItem("Select...", "0")); //Die erste 0 ist die Stelle des Indexes (in diesem Falle an "1." Stelle)
                                                                                //("Select...", "0") --> is a String and the Value (NOTE: we could also just put in the "Select..." without the Value)
            }
        }
        protected void Page_Load(object sender, EventArgs e)
        {
            //this method executes BEFORE any event method on
            //      EACH processing of this web page

            //this is a great place to do common code that is
            //      required on EACH process of the page
            //Example: empty out old messages
            MessageLabel.Text = "";

            //this is an excellent place to do page initialization
            //  of controls on the 1st pass
            //checking the 1st time for this page uses the post back flag
            //Page.IsPostBack; this is a boolean value(true or false)
            if (!Page.IsPostBack)        //if(!false) => true
            {
                //if the page is not PostBack, it means that this
                //  is the 1st time the page has been displayed

                //simulate the loading of the dropdownlist via a
                //  dataset from a database call

                //create a collection of instances (class objects)
                //  that will be used to load the dropdownlist
                //each instance will represent a record on the
                //  database dataset
                //to accomplish is simulation, we will create a
                //  class and use it with a List<T>
                //the <T> in this example is the class DDLData
                List <DDLData> DDLCollection = new List <DDLData>();
                DDLData        aninstance    = new DDLData();
                aninstance.ValueId     = 1;
                aninstance.DisplayText = "COMP1008";
                DDLCollection.Add(aninstance);
                aninstance = new DDLData(3, "DMIT1508");
                DDLCollection.Add(aninstance);
                DDLCollection.Add(new DDLData(4, "DMIT2018"));
                DDLCollection.Add(new DDLData(2, "CPSC1517"));

                //sorting of a List<T
                // (x,y) are placeholders representing any 2 records at any
                //      given time during the sort
                // => (lamda symbol) is part of the delegate syntax, I suggest
                //          that you read this symbol as "do the following"
                // comparing x to y is ascending
                // comparing y to x is descending
                DDLCollection.Sort((x, y) => x.DisplayText.CompareTo(y.DisplayText));

                //place the data collection set into the dropdownlist control
                //3 step to this process

                //a) assign the data collection set to the control
                CollectionList.DataSource = DDLCollection;

                //b) in this step you will assign the value that will
                //      be diplayed to the user and the value that will
                //      be associated and return from the control wher
                //      the user picks a particular selection
                //in the <select> control, this data was step using the <option>
                //  <option value="xxxx">display string</option>
                //this information is assigned to the DDL control by use
                //   of the property name in your collection

                //2 styles
                //  a) physical string of the field name
                CollectionList.DataValueField = "ValueId";
                //  b) OOP style coding
                CollectionList.DataTextField = nameof(DDLData.DisplayText);

                //c) bind your data source to your control
                CollectionList.DataBind();

                //d) optionally
                //  add a prompt line to your dropdownlist
                CollectionList.Items.Insert(0, new ListItem("select ...", "0"));
            }
        }
        protected void Page_Load(object sender, EventArgs e)
        {
            // this method will execute on EACH and EVERY post back to this page

            // this method will execute on the first display of this page

            // to determine if the page is new or postback, use the IsPostBack property

            // this method is often used as a general method to reset fields or controls at the start of page processing

            // the label MessageLabel is used to display messages to the user. Old messages should be removed from this control on each pass

            // how do we reference a control on the .aspx form? notice that each form control has an ID, we can use this.

            // each control is an object, therefore we will be altering property values

            MessageLabel.Text = "";

            if (!Page.IsPostBack) // "!" means NOT
            {
                // here we are creating an instance of List<T> for the "fake database" data
                DataCollection = new List <DDLClass>();

                // add data to the collection that we just created, one entry at a time
                DataCollection.Add(new DDLClass(1, "COMP1008"));
                DataCollection.Add(new DDLClass(2, "DMIT1508"));
                DataCollection.Add(new DDLClass(3, "CPSC1517"));
                DataCollection.Add(new DDLClass(4, "DMIT2018"));

                // one benefit of using a list vs an array is that we can easily sort them, we do this below using the .Sort() method

                // (x, y) represents ANY two entries in the data collection at ANY point in time

                // the lamda symbol "=>" basically means "do the following"

                // .CompareTo() is a mehtod that will compare two items and return the result

                // this result is then interpreted by the Sort() method to determind if the order needs to be changed

                // x vs y is ascending
                // y vs x is descending

                DataCollection.Sort((x, y) => x.DisplayField.CompareTo(y.DisplayField));

                // place the collection into the dropdownlist
                // a) assign the collection to the control (ID = CollectionList

                CollectionList.DataSource = DataCollection;

                // b) assign the value and display portions of the dropdownlist to specify properties of the data class
                CollectionList.DataTextField  = nameof(DDLClass.DisplayField);
                CollectionList.DataValueField = nameof(DDLClass.ValueField);

                // c) bind the data to the collection (aka physical attachment)
                CollectionList.DataBind();

                // d) you may wish to add a prompt line at the beginning of the list of data within the dropdown list

                CollectionList.Items.Insert(0, "select...");
            }
        } // closes PageLoad