如何打开表单，然后在C＃上X秒钟后将其关闭？

Question

I need to open a form on C# and then have it close automatically after, say, 5 seconds.. The thing is, I need the form to be closed from the form it was opened from because the form I am opening is sometimes opened from another form without being automatically closed.

I've tried this:

        private void button6_Click(object sender, EventArgs e)
    {
        GetNumber gtn = new GetNumber();
        gtn.Show();
        System.Threading.Thread.Sleep(6000);
        gtn.Hide();
        gtn = null;
    }

But the form was messed up when it started, same happened when I tried with a timer. Anybody know how to solve my problem?

Answer 1

As itsme86 said, timers would work for what you are trying to do. If you are in .Net 4.5 or greater you can use the async/await features.

At its core, you need to free up the UI thread to continue on its way. Your Thread.Sleep is putting the UI thread out of commission. Using a timer or the async/await allows the UI thread to launch your dialog and process any user actions.

private async void button6_Click(object sender, EventArgs e)
{
    GetNumber gtn = new GetNumber();
    gtn.Show();
    await Task.Delay(6000);
    gtn.Hide();
    gtn = null;
}

Answer 2

A timer would be the correct approach:

private void button6_Click(object sender, EventArgs e)
{
    GetNumber gtn = new GetNumber();
    gtn.Show();

    System.Timers.Timer timer = new Timer(6000);
    timer.Elapsed += (_, _2) => { Invoke((MethodInvoker)delegate { gtn.Close(); }); };
    timer.Start();
}