WinForms Dialog strange behaviour

Question

Very strange.
An open dialog closes after selecting a file.
The dialog consists of a bottom panel with
OK- and Cancel-buttons.
A usercontrol will fill the rest of the clientarea.
Since this usercontrol doesn't allow adding a new item,
a second usercontrol will overlap its top part.
The second usercontrol (SelectControl) has a textbox and a selectbutton.
After opening the dialog, I click the selectbutton and
select a file, using OpenFileDialog.
But when I confirm the selection (OK), SelectControl is gone,
my Dialog is gone and I am where I opened the Dialog.
I use usercontrols very often but never had a problem like this.
Any idea what'S going the wrong way here?
thanks in advance for your help.

Eliana Blake · Answer

It appears that the behavior you are experiencing with your WinForms Dialog is indeed puzzling. Based on the description provided, it seems that the issue lies in the interaction between the OpenFileDialog and your user controls setup. When using OpenFileDialog to select a file within a user control (SelectControl in this case) that overlaps another user control, there might be a focus-related problem that causes the main dialog to close unexpectedly upon confirming the file selection. This behavior could be due to how the OpenFileDialog interacts with the user controls and the parent dialog's focus management. One possible solution to this issue could involve ensuring that the focus is returned correctly to the parent dialog after the file selection process. You may need to handle events such as the FileOk event of the OpenFileDialog to properly manage the closing behavior and focus restoration within the dialog. Here's a general example of how you could structure the event handling within your SelectControl user control: // Inside SelectControl user control private void selectButton_Click(object sender, EventArgs e) { using (OpenFileDialog openFileDialog = new OpenFileDialog()) { if (openFileDialog.ShowDialog() == DialogResult.OK) { // Perform any necessary actions with the selected file // Notify the parent form/dialog that a file has been selected and it should not close OnFileSelected?.Invoke(this, EventArgs.Empty); } } } In this example, `OnFileSelected` is a custom event that you can define in your SelectControl user control to notify the parent dialog that a file has been selected and it should not close. The parent dialog can then handle this event and prevent premature closing. Overall, by carefully managing focus, event handling, and the interaction between user controls and dialogs, you should be able to address the unexpected closing behavior you are encountering. If you continue to face challenges, further debugging and possibly simplifying the user control interactions might help isolate the root cause of the problem. I hope this sheds some light on the potential issue you are facing with your WinForms Dialog behavior. If you need more specific guidance or have further details to share, feel free to provide additional information for a more tailored solution.