private void button1_Click(object sender, EventArgs e) //save button for Form4. Note: we differentiate between insert and update operation
{
CompanyDBDataContext dc = new CompanyDBDataContext(); //establish connection
if (textBox1.ReadOnly == false) // insert operation is happening
{
Employee obj = new Employee();
obj.Eno = int.Parse(textBox1.Text);
obj.Ename = textBox2.Text;
obj.Job = textBox3.Text;
obj.Salary = decimal.Parse(textBox4.Text);
obj.Dname = textBox5.Text;
dc.Employees.InsertOnSubmit(obj); //pending insert
dc.SubmitChanges(); //commit the data
MessageBox.Show("Record inserted into the table.");
}
else //update operation triggered on Form3 and now new entries must be inserted in this Form4
{
Employee obj = dc.Employees.SingleOrDefault(E => E.Eno == int.Parse(textBox1.Text)); //reference to existing record. Use lambda to access values
obj.Ename = textBox2.Text; //user modified value is in textbox
obj.Job = textBox3.Text;
obj.Salary = decimal.Parse(textBox4.Text);
obj.Dname = textBox5.Text;
dc.SubmitChanges();
MessageBox.Show("Record updated in the table.");
}
{
}
}
private void Button1_Click(object sender, EventArgs e)
{
CompanyDBDataContext d = new CompanyDBDataContext();
if (textBox1.ReadOnly == false) // as we this method will be called while we press insert as well a update , so the difference between the insert and the update is the textBox.ReadOnly as false or true. Hence we can use it as a condition to differentiate if its a insert or update.
{
Employee obj = new Employee(); // to access the Employee class we created the instance
//Assigning the values to the property
obj.Eno = int.Parse(textBox1.Text); //here we have to explicitly convert the string value to int .int.Parse converts strings to int.
obj.Ename = textBox2.Text; //it is string
obj.Job = textBox3.Text;
obj.Salary = decimal.Parse(textBox4.Text); // because we used type money in database so we have to convert into decimal or int
obj.Dname = textBox5.Text;
d.Employees.InsertOnSubmit(obj); //InsertOnSubmit(obj) inserts the record to the table but wont commit (appending k)
d.SubmitChanges(); // this will commit the data changes
MessageBox.Show("The Record has been inserted into the table");
}
else
{
//Creating a refernce to an existing record
Employee obj = d.Employees.SingleOrDefault(E => E.Eno == int.Parse(textBox1.Text)); //here the Eno. becomes a refernce to the existing records
obj.Ename = textBox2.Text; //now if user doesnt modifies it then the old value will be overridden to the old values but if the user modifies it with a new value then the new value overrides the old value.
obj.Job = textBox3.Text;
obj.Salary = decimal.Parse(textBox4.Text);
obj.Dname = textBox5.Text;
d.SubmitChanges(); // this will commit the data changes
MessageBox.Show("The Record has been Updated into the table", "Success", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
}
private void button3_Click(object sender, EventArgs e) //Delete button
{
if (dgView.SelectedRows.Count > 0)
{
if (MessageBox.Show("Are you sure of deleting the selected record?", "Confirmation", MessageBoxButtons.YesNo, MessageBoxIcon.Question) == DialogResult.Yes) ////user clicked yes
{
int Eno = Convert.ToInt32(dgView.SelectedRows[0].Cells[0].Value);
Employee obj = dc.Employees.SingleOrDefault(E => E.Eno == Eno); //becomes reference of existing record
dc.Employees.DeleteOnSubmit(obj);
dc.SubmitChanges();
LoadData();
}
}
else
{
MessageBox.Show("Please select a record to delete.", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
}
private void Button3_Click(object sender, EventArgs e)
{
if (dgView.SelectedRows.Count > 0)
{
if (MessageBox.Show("Are you sure you want to delete this particular row", "Confirmation", MessageBoxButtons.YesNo, MessageBoxIcon.Question) == DialogResult.Yes)
{
int Eno = Convert.ToInt32(dgView.SelectedRows[0].Cells[0].Value); // this converts the object to integer
Employee obj = dc.Employees.SingleOrDefault(E => E.Eno == Eno); // here now the obj becomes the refernce of the existing record
dc.Employees.DeleteOnSubmit(obj); // this deletes the record on a pending delete state, that is it hasnt commited the data
dc.SubmitChanges(); // this will commit the data
MessageBox.Show("The record has been sucessfully deleted!!", "Success!!", MessageBoxButtons.OK, MessageBoxIcon.Information);
LoadData();
}
}
else
{
MessageBox.Show("Select the rows you want to delete first then only click Update", "There was an Error", MessageBoxButtons.OK, MessageBoxIcon.Warning);
}
}
