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Is there a way to re-use an already closed WPF Window instance

Answer 1

+1 A:

What exactly is it that makes it so important to use the same window? If you are using MVVM, you could just reuse the viewmodel for a new window.

Botz3000 2009-08-07 01:12:28

But I want to eliminate the cost of a new Window instance creation. So checking whether there is a re-usability scope and use ShowDialog() again on the instance.

Jobi Joy 2009-08-07 18:24:00

Is your window that expensive to create?

Botz3000 2009-08-08 15:14:37

Martin Doms's answer is correct, but I'm very curious about this question myself. Is it possible you are overestimating the overhead of creating this view, especially if you are using MVVM and keeping the VM around?

Anderson Imes 2009-08-09 05:54:37

Answer 2

+6 A:

You need to override the wInstance OnClosing method to set the window visibility to hidden and cancel the close event.

 protected override void OnClosing(System.ComponentModel.CancelEventArgs e)
    {
        this.Visibility = Visibility.Hidden;
        e.Cancel = true;
    }

Martin Doms 2009-08-09 03:28:48

Thanks Martin, this is the answer to a question that I was asking myself the other day.

Dennis Roche 2009-08-09 22:17:11

I have the same problem here and although this stopped the exception when I try to use the window again, it is preventing the ShowDialog() from returning true when I would expect. Do you have any suggestions about this?

EasyTimer 2010-10-18 19:47:40

The return for ShowDialog() indicates how the dialog was disposed of. If this information is important to you then you will need to actually dispose of the window when it is closed, so you shouldn't cancel the close event, and instead instantiate a new Window when you want to reopen it. If state information of the window is important consider the memento pattern.

Martin Doms 2010-10-27 06:26:09

Answer 3

A:

I'm reusing a window as a Dialog that uses a treeview and the client wants the tree branches to remain open for a more selections.

The override worked for re-use, and the branches stay expanded.

I'm not using a view model to keep it simple as it is a read only selection dialog. But since I can't seem to clear the selection yet, I may have to switch to a view model.

Dave 2010-04-29 15:49:08

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Is there a way to re-use an already closed WPF Window instance

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