private static RosterItem GetRosterItem(int NextId)
{
RosterItem returnValue = new RosterItem();
//were only collecting 3 of the properties
string FirstName = "";
string LastName = "";
string Gender = "";
//create a validator with our new fluent validator class
//take alook at the comments in the RosterItemValidator class
RosterItemValidator validator = new RosterItemValidator();
//start with the object as invalid
bool IsValid = false;
//this condition should always be triggered the first time through
//then only triggered if a property is invalid
while (!IsValid)
{
//this prevents a user having to re-enter valid values
//if the field has an error we blank it out
if (String.IsNullOrEmpty(FirstName))
{
//get the first name
Console.WriteLine("Enter a FirstName: ");
FirstName = Console.ReadLine();
}
if (String.IsNullOrEmpty(LastName))
{
//get the lastname
Console.WriteLine("Enter a LastName:");
LastName = Console.ReadLine();
}
if (String.IsNullOrEmpty(Gender))
{
//get the gender
Console.WriteLine("Enter a Gender:");
Gender = Console.ReadLine();
}
//assign our values to the roster item
returnValue = new RosterItem
{
ID = NextId,
FirstName = FirstName,
LastName = LastName,
Gender = Gender
};
//check to see if the values are valid
ValidationResult results = validator.Validate(returnValue);
//set the variable for the loop
IsValid = results.IsValid;
//loop through all of the errors and display
//an error message for each error
foreach (var failure in results.Errors)
{
//change the foreground color to red
Console.ForegroundColor = ConsoleColor.Red;
//display the error (blank line in front and behind)
Console.WriteLine("");
Console.WriteLine($"Property {failure.PropertyName} failed validation. \r\nError was: {failure.ErrorMessage}");
Console.WriteLine("");
//reset the console color
Console.ResetColor();
//blank out the bad value so it will be repeated to the user
switch (failure.PropertyName)
{
case "FirstName":
FirstName = "";
break;
case "LastName":
LastName = "";
break;
case "LastName.Length":
LastName = "";
break;
case "Gender":
Gender = "";
break;
}
}
}
return(returnValue);
}
//this method is declared as static so it can be run in
//another static method
//I've changed this method a bit to read directly into a List<>
//instead of just a string
private static List <RosterItem> ReadFileToRosterList(string FileName)
{
//I always like to start my method by declaring the return
//value when there is a value to be returned
List <RosterItem> returnValue = new List <RosterItem>();
//set up a counter and line variable
int counter = 0;
string line;
//always be aware of what resources your program is using
//The C# garbage collector does a pretty good job of maintaining program
//resources, but you shouldn't count on it whe using librarys that
//acces external resources sunch as files or databases
//create a progress bar using a nuget package called ShellProgressBar
//https://github.com/Mpdreamz/shellprogressbar
//found this by googling "c# console app progress bar"
//the max number of items to process
var maxTicks = File.ReadLines(FileName).Count();
//create a progress bar
using (var pbar = new ProgressBar(maxTicks, "Starting", ConsoleColor.DarkGreen))
{
//we use a "using" statement to make sure the file resource is released from
//memory. A try..catch..finally can be used but a "using" statement is easier.
using (System.IO.StreamReader file = new System.IO.StreamReader(FileName))
{
while ((line = file.ReadLine()) != null)
{
//update the progress bar
pbar.Tick("Currently processing " + counter);
//skip the first line
if (counter > 0)
{
//returnValue += line;
RosterItem myRosterItem = new RosterItem();
string[] myLineArray = line.Split(',');
myRosterItem.ID = Convert.ToInt32(myLineArray[0]);
myRosterItem.FirstName = myLineArray[1];
myRosterItem.LastName = myLineArray[2];
myRosterItem.Email = myLineArray[3];
myRosterItem.TeamColor = myLineArray[4];
myRosterItem.Gender = myLineArray[5];
myRosterItem.Position = myLineArray[6];
//now that we have a completed object
//add it to the returnvalue (Remember the special List<> gives us the ad method automatically)
returnValue.Add(myRosterItem);
//artifically add a little time to the process
System.Threading.Thread.Sleep(250);
}
counter++;
}
}
}
return(returnValue);
}
static void Main(string[] args)
{
//Remember a backslash is a special escape character
//If you want a line with a quote in the middle of the line you have to "escape"
//the special meaning of a quote. Uncomment each line and see which one
//passes
//string illegalQuoteString = "Don't "Quote" me on that!";
string properlyEscapedQuoteString = "Don't \"Quote\" me on that!";
//The same way the Dollar sign can be used for string interpolation
//the @ symbol can be used to automatically escape characters between
//the quotes. So a file path stored in a variable could be assigned like:
string myExampleFilePath = "C:\\Some\\Path\\To\\A\\File";
//but it's easier to use the @
string myBetterExampleFilePath = @"C:\Some\Path\To\A\File";
//both are correct but I think the second one is easier to read
Console.WriteLine("*** Creating the list by paring the file ourselves ***");
Console.WriteLine("Press Enter to continue...");
Console.ReadLine();
//Create a Roster --A list of RosterItems (Yes I renamed them since the meetup)
//A list is nothing more than more than one of a class
//This is a generic list List<FillInTheBlankWithYourObject>
//It automatically gives us methods like Add(), Remove(), Find() and FindAll()
//The <> angle brackets is a SIGNIFICANT pattern in c# you will find other libraries that
//use the same pattern. When you see them you usually fill in the blank with a TYPE
//The next line instantiates the generic list
List <RosterItem> myRoster = new List <RosterItem>();
//using System.IO file methods we can open the file and Read each line one at a time
//Let's read the CSV file straight into our list
//we don't have to include the entire file path since we set the file to "Copy Always"
//this places the file in the same debug directory as our EXE
myRoster = ReadFileToRosterList("Roster.csv");
//loop through the list and write the first and last name of each roster item
//along with their position
foreach (RosterItem item in myRoster)
{
//by putting the dollar sign in fromt of the string we're telling
//c# that we want the variable names inside the string to be translated
//to their values (String Interpolation)
Console.WriteLine($"Player: {item.FirstName} {item.LastName}, Position: {item.Position}");
//lets add some drama by adding a quarter a second wait between lines
System.Threading.Thread.Sleep(250);
}
Console.WriteLine("");
Console.WriteLine("*** Now let's do it using the file helpers library ***");
Console.WriteLine("Press Enter to continue...");
Console.ReadLine();
//Convert a CSV file to an object list
//using FileHelpers (downloaded via nuget)
var engine = new FileHelperEngine <RosterItem>();
//we don't want to read the header of the file
engine.Options.IgnoreFirstLines = 1;
//Now we do it an easier way
var result = engine.ReadFile("Roster.csv");
//we managed to convert the file to our class
//and only had to use 4 lines of code and add
//an attribute of [DelimitedRecord(",")] to the class
//pretty easy
//lets print the info to screen again
//this time we'll use a for loop instead of a foreach loop
//loop through the list and write the first and last name of each roster item
//along with their position
for (int i = 0; i < myRoster.Count; i++)
{
//assign the item in the array to item
//I think this makes the code a bit cleaner
//you can, of course, just use myRoster[i].FirstName
RosterItem item = myRoster[i];
Console.WriteLine($"Player: {item.FirstName} {item.LastName}, Position: {item.Position}");
//lets add some drama by adding a quarter a second wait between lines
System.Threading.Thread.Sleep(250);
}
//so when should we use a for loop insatead of a foreach? when we need to
//track the item number or when we need a counter for the items we're looping through
//now that we have the list of items
//let's "Serialize" them
//The easy way to think about serialzation is that it's the process of
//turning an object or object list into text (usually XML or JSON)
//deserilization is the process of taking serialized text and turning it
//back inot the object or object list
//this code requires the XML.Serialzation library
Console.WriteLine("");
Console.WriteLine("*** Now let's serialize our list ***");
Console.WriteLine("Press Enter to continue...");
Console.ReadLine();
// Create a new XmlSerializer instance with the type of the test class
XmlSerializer SerializerObj = new XmlSerializer(typeof(List <RosterItem>));
// Create a new filestream so we can write the serialized object to a file
using (TextWriter WriteFileStream = new StreamWriter("roster.xml"))
{
//serialize our list<>
SerializerObj.Serialize(WriteFileStream, myRoster);
}
//open the xml file with notepad
//how did I figure out how to open a file in notepad?
//easy I googled "C# Open File Notepad"
Console.WriteLine("Opening our serialized data in notepad...");
System.Threading.Thread.Sleep(500);
Process.Start("notepad.exe", "roster.xml");
Console.WriteLine("");
Console.WriteLine("*** Now let's deserialize our list ***");
Console.WriteLine("Press Enter to continue...");
Console.ReadLine();
//Deserialze the XML file
// Create a new file stream for reading the XML file
using (FileStream ReadFileStream = new FileStream("roster.xml", FileMode.Open, FileAccess.Read, FileShare.Read))
{
// Load the object saved above by using the Deserialize function
//the parenthesses mean we are "casting" the return object to that type
List <RosterItem> reLoadedRoster = (List <RosterItem>)SerializerObj.Deserialize(ReadFileStream);
//how many items are in our reloaded list
Console.WriteLine($"We reloaded {reLoadedRoster.Count} items from our xml file.");
}
Console.WriteLine("");
Console.WriteLine("*** Now let's add a new item to the list ***");
Console.WriteLine("Press Enter to continue...");
Console.ReadLine();
//one of the challanges of adding a new entry is that it must be valid data
//whenever possible you should prevent the user from entering bad data
//in a windows or web application this is easier since most data being entered
//is from a control (dropdown list or textbox), it's much more difficult to validate
//when the user can only enter text, like in our console app
//we're going to need to get the highest ID number so the next entry
//will have a unique ID
//This is a bit of a cheat since I know the items in the file we read in are numbered sequentially
//so a simple count of the number of the items in the list + 1 should give us the next ID
//there are probably a 100 other ways we can do this
int NextId = myRoster.Count + 1;
//get a new roster item
//I broke this into its own method
RosterItem newRosterItem = GetRosterItem(NextId);
//Add the new item to the list
myRoster.Add(newRosterItem);
Console.WriteLine($"There are now {myRoster.Count} items in our list.");
Console.WriteLine($"You just added {newRosterItem.FirstName} {newRosterItem.LastName} to the roster.");
//Console.WriteLine(myString);
Console.ReadLine();
}