WPF window owner property issue

Question

I have a WPF MainWindow where I can open a second one as follow, taking as an example this post:

var win = new CalibrationWindow(){Owner = this};
win.ShowDialog();

Rarely happens that I have the following runtime exception "cannot set owner property to a window that has not been shown previously".

Do you have any suggestions? Thanks in advance.

That probably indicates that `this` - your main window - has not been shown yet. — Pieter Witvoet, Feb 06 '17 at 13:44
No, the Main Window is shown because I open the second window only after having pressed a button. — ctt_it, Feb 06 '17 at 14:02

score 0 · Answer 1 · edited May 23 '17 at 11:47

0

Handle the StateChanged or Activated event of the window and set the Owner property in this event handler as suggested here:

var win = CalibrationWindow();
this.Activated += (s, e) => { win.Owner = this; };
win.ShowDialog();

edited May 23 '17 at 11:47

Community

answered Feb 06 '17 at 13:45

mm8

What if I can open several Windows? If I do the following private void MainWindow_OnActivated(object sender, EventArgs e) { ((Window) sender).Owner = this; } I have an eception when I open the window at the first time. – ctt_it Feb 06 '17 at 13:59
The parent window *must* have been opened before you can use it as an owner of the child window. – mm8 Feb 06 '17 at 14:01
Sure, the MainWindow is shown otherwise I can't press the button in order to show the second window. – ctt_it Feb 06 '17 at 14:09

1 Answers1