Tray application allow system to kill my program when logouting or exiting

Question

My program is starting with windows, I have such code to prevent exiting application when user hits exit button:

    protected override void OnClosing(CancelEventArgs e)
    {
        this.ShowInTaskbar = false;
        e.Cancel = true;
        this.Hide();
    }

It is working very well, but when I want to turn off computer, every time I get screen like 'One or more application cannot be exited. Cancel - Exit despite this.

How can I allow windows to normally exit my application, but also prevent user from exiting it when click red exit button?

You better post an answer your self instead of adding an answer to your question.... http://blog.stackoverflow.com/2011/07/its-ok-to-ask-and-answer-your-own-questions/ — rene, Nov 16 '14 at 11:38

score 4 · Accepted Answer · edited May 23 '17 at 12:27

4

See How to detect Windows shutdown or logoff.

In the SessionEnded event handler, set a boolean like sessionEnded and in your OnClosing test for that value:

if (!sessionEnded)
{
    e.Cancel = true;
    this.Hide();
}

edited May 23 '17 at 12:27

Community

1
1

answered Nov 16 '14 at 11:09

CodeCaster

147,647
23
218
272

score 1 · Answer 2 · answered Nov 16 '14 at 11:52

This helped (thanks to CodeCaster):

    private static int WM_QUERYENDSESSION = 0x11;
    private static bool systemShutdown = false;
    protected override void WndProc(ref System.Windows.Forms.Message m)
    {
        if (m.Msg == WM_QUERYENDSESSION)
        {
            systemShutdown = true;
        }

        // If this is WM_QUERYENDSESSION, the closing event should be
        // raised in the base WndProc.
        base.WndProc(ref m);

    } //WndProc 

    protected override void OnClosing(CancelEventArgs e)
    {
        this.ShowInTaskbar = false;
        if (!systemShutdown)
        {
            e.Cancel = true;
            this.Hide();
        }
    }

Tray application allow system to kill my program when logouting or exiting

2 Answers2