How to open Windows Form from with mdiParent in timer method?

Question

I have a MainForm and method which opens new window:

private void OpenWindow(object source, ElapsedEventArgs e)
{
    var form = new SomeForm();
    form.MdiParent = this;
    form.Show();
}

And timer:

System.Timers.Timer timer = new System.Timers.Timer();
timer.Elapsed += new ElapsedEventHandler(OpenWindow);
timer.Interval = 10000;
timer.Enabled = true;

And it throws error on setting MdiParent: form.MdiParent = this;

Cross-thread operation not valid: Control 'MainForm' accessed from a thread other than the thread it was created on.

How can I solve this problem?

Try using another Timer. https://stackoverflow.com/questions/10317088/why-there-are-5-versions-of-timer-classes-in-net — user11909, Oct 19 '18 at 10:35
Possible duplicate of [Writing to a TextBox from another thread?](https://stackoverflow.com/questions/519233/writing-to-a-textbox-from-another-thread) — rs232, Oct 19 '18 at 10:56
@user2190035 your idea helped me, if you write it as detailed answer, I'll accept it. P.S thanks — godot, Oct 19 '18 at 11:00

score 1 · Accepted Answer · answered Oct 19 '18 at 11:36

1

You could use one of the other Timers because they handle the threading differently.

Explained here: Why there are 5 Versions of Timer Classes in .NET?

answered Oct 19 '18 at 11:36

user11909

1,235
11
27

Salah Akbari · Answer 2 · 2018-10-19T10:53:53.933

0

Based on Threading Model article, I think this should works in your cas:

var form = new SomeForm();
if (form.InvokeRequired)
{
    form.Invoke(new MethodInvoker(delegate {
    form.MdiParent = this;
    }));
}
form.Show();

Or like this:

Invoke(new Action(() =>
{
    form.MdiParent = this;
    form.Show();
}));

edited Oct 19 '18 at 10:53

answered Oct 19 '18 at 10:41

Salah Akbari

39,330
10
79
109

thank you for answer, but in this form I use xtraTabControl and I'm getting following error: "Current thread must be set to single thread apartment (STA) mode before OLE calls can be made. Ensure that your Main function has STAThreadAttribute marked on it." – godot Oct 19 '18 at 10:50
@godot Have a look at my updated answer. it is another approach. – Salah Akbari Oct 19 '18 at 10:54
@godot Or you might need to add the `[STAThread]` attribute on your method. – Salah Akbari Oct 19 '18 at 10:59
thanks for answer again, +1 from me. Got another solution, just used another timer – godot Oct 19 '18 at 11:53

How to open Windows Form from with mdiParent in timer method?

2 Answers2