Automatically close messagebox in C#

You will need to create your own Window, with the code-behind containing a loaded handler and a timer handler as follows:

private void Window_Loaded(object sender, RoutedEventArgs e)
{
    Timer t = new Timer();
    t.Interval = 3000;
    t.Elapsed += new ElapsedEventHandler(t_Elapsed);
    t.Start();
}

void t_Elapsed(object sender, ElapsedEventArgs e)
{
    this.Dispatcher.Invoke(new Action(()=>
    {
        this.Close();
    }),null);
}

You can then make your custom message box appear by calling ShowDialog():

MyWindow w = new MyWindow();
w.ShowDialog();

The System.Windows.MessageBox.Show() method has an overload which takes an owner Window as the first parameter. If we create an invisible owner Window which we then close after a specified time, it's child message box would close as well.

Here is the complete answer: https://stackoverflow.com/a/20098381/2190520