C# 在 Form_FormClosing 中单击是时不断弹出对话框

Question

Adding an event in my C# winForms the FormClosing but the dialog keeps pop-up after adding the code Close()

 private void AdminPanel_FormClosing(object sender, FormClosingEventArgs e)
    {
        DialogResult result = (MessageBox.Show(this,
                                "Are you sure you want to close the Application?",
                                "Exit",
                                MessageBoxButtons.YesNo, MessageBoxIcon.Question));
        if (result == DialogResult.Yes)
        {
            //dialog keeps poping up when i try to close the form
            Close();
        }
        else {
            e.Cancel = true;
        }
    }

Answer 1

Have you tried removing the Close(); call? You're already in a Closing event handler – unless you cancel the close, it's going to happen anyway.

Answer 2

You don't need to add a call to Close method inside FormClosing because you are already in the form close call pattern of Application.

You need to write:

private void AdminPanel_FormClosing(object sender, FormClosingEventArgs e)
{
  var result = MessageBox.Show(this,
                               "Are you sure you want to close the Application?",
                               "Exit",
                               MessageBoxButtons.YesNo, MessageBoxIcon.Question) );
  if ( result != DialogResult.Yes )
  {
    e.Cancel = true;
  }
}

• If DialogResult.Yes then it does nothing to e.Cancel and the form is closed and the FormClosed event is called.

• If e.Cancel is set to true then the Close call is cancelled by the Application manager and FormClosed is not called.

If you add a call to Close in FormClosing you will get a stack overflow: the box is shown and shown and shown and shown and shown and so on without end as long as you click on Yes , unless you click on No ...

If you want to force the application ending you can use in the FormClosed event:

Environment.Exit(0);

But perhaps you have something somewhere that prevents the close.

Do you have code in FormClosed ? Does it throw an exception? Else you need to catch it because it stops the close.