c# trying to get an event to fire when a different window closes

I have one form that has an option to open another (dialogue)开发者_如何学Go. I want an event to fire when the second window closes. The first form is named frmMain() the other is frmAddEmployee(). Heres what I have: in frmMain()

//create and open the second window
public void (object sender, EventArgs e)
{
     frmAddEmployee addEmp = new frmAddEmployee();
     addEmp.ShowDialogue();
}

//create event to handle addEmp being closed
public void addEmp_Closing(object sender, EventArgs e)
{
     PopulateEmployeeList();
}

I'm not sure the event is being recognized as an event. What am I doing wrong?

Events in C# have to be registered manually - the C# compiler will not automatically register method as an event handler based just on the name of the method. You need:

 frmAddEmployee addEmp = new frmAddEmployee(); 
 addEmp.Closing += addEmp_Closing; // Register event handler explicitly
 addEmp.ShowDialogue(); 

Automatic registration of events is done in ASP.NET and Visual Basic has Handles clause, but in C#, you need to use the += operator to specify that some method should be called when an event occurs.

Assuming ShowDialogue means ShowDialog, then it shows the form modally and you don't need an event handler:

//create and open the second window
public void (object sender, EventArgs e)
{
     frmAddEmployee addEmp = new frmAddEmployee();
     addEmp.ShowDialog();
     PopulateEmployeeList();
}

If you don't show the second form modally, then you can hook up the event handler before showing the form like this:

public void (object sender, EventArgs e)
{
     frmAddEmployee addEmp = new frmAddEmployee();
     addEmp.FormClosed += AddEmpClosed;
     addEmp.Show();
}

private void AddEmpClosed(object sender, FormClosedEventArgs e)
{
     PopluateEmployeeList();
}

There is Closing and Closed events which you can register for on the Form. You are registered for neither, unless your registration is taking place somehwere else?

Before you call addEmp.ShowDialog() you need to set your method to handle the Closing event:

frmAddEmployee addEmp = new frmAddEmployee();
addEmp.Closing += addEmp_Closing;
addEmp.ShowDialogue();