如何设置对话框的所有者窗口

Question

I've got a WPF application with these two separated things:

• Main Window
• Dialog box (prompt out when the close button on the main window is clicked, if [yes] is clicked, whole application will close, if [no] is clicked, back to the main window)

Here's my code when the close button on main window is clicked:

private void CloseBtn_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
                SPMessageBox msgBox = new SPMessageBox();
                msgBox.Owner = this;
                msgBox.ShowDialog();          
        }

And here's the code when the [yes] and [no] button on the dialog box are clicked:

public void Yes_Click(object sender, RoutedEventArgs e)
        {
            Application.Current.Shutdown();
        }

private void No_Click(object sender, RoutedEventArgs e)
        {
            this.Close();
        }

When the [no] button is clicked, the whole application stops working. Is it because the owner is changed so it can't get back to the main window? How to handle this problem so that after the [no] button is clicked it can go back to the main window?

Answer 1

Not sure about the owner issue or what happens when you call this.Close(), but this is how I've learned to handle dialog clicks:

private void Yes_Click(object sender, RoutedEventArgs e)
{
    this.DialogResult = true;
}
private void No_Click(object sender, RoutedEventArgs e)
{
    this.DialogResult = false;
}

Provided that SPMessageBox inherits from Window this should close the dialog and let you handle the result in CloseBtn_MouseLeftButtonDown like this:

if (msgBox.ShowDialog() == true)
   Application.Current.Shutdown();

The "== true" is necessary since the return type is bool? (nullable bool).

More info under "Setting the Modal Dialog Result" a bit down on this MSDN page

Answer 2

As said in my comment, I prefer the Closing event of the window to cancel it if necessary.

In this case it is important that SPMessageBox returns a value that determine the user choice of closing the Application. It can be done with the DialogResult property:

public void Yes_Click(object sender, RoutedEventArgs e)
{
    this.DialogResult = true;//close application
    this.Close();
}

private void No_Click(object sender, RoutedEventArgs e)
{
    this.DialogResult = false;//keep application open
    this.Close();
}

And here is the calling of the dialog:

private void Window_Closing(object sender, CancelEventArgs e)
{
    SPMessageBox msgBox = new SPMessageBox();
    msgBox.Owner = this;
    if (msgBox.ShowDialog() == false)
    {
        e.Cancel = true;//cancel closing the window
    }
}

But I am not sure if this is solves the real problem. I tested also your code in a new WPF application and got no problems with it. I think there must be another part in your code, that makes problems. The assignment of Owner should not be problematic.

Answer 3

You should set the .DialogResult property to properly close a dialog. The code that opens the dialog should check the result and actually perform the operation.