Closing all mdichildren forms

[Dylan van Heerden]

The following doesn't seem to work... foreach (Form f in this.MdiChildren) { f.Close(); } I recieve the following error "Specified cast is not valid." Am I missing something. :confused: Sweet

[Heath Stewart]

You can't change a collection while enumerating it. Calling Close ultimately will change the collection. Instead, use:

for (int i=0; i<MdiChildren; i++)
{
Form f = (Form)MdiChildren[i];
f.Close();
}

Microsoft MVP, Visual C# My Articles

[Dylan van Heerden]

Right now comes the this. I've got 3 mdichildren forms and when I click the button to close all the forms, only 2 closes and 1 stays open until I click the button again. Is it because I did the following like u showed except I added .Length. for (int i = 0; i < MdiChildren.Length; i++) { Form f = (Form)MdiChildren[i]; f.Close(); } Sweet

[Heath Stewart]

Sorry - I made a mistake. You should either run through the array backward or make a copy of the array (and forgetting .Length was a typo - it's only sample code):

for (int i=MdiChildren.Length; i >= 0; i--)
{
Form f = MdiChildren[i]; // Cast really not necessary
f.Close();
}

Microsoft MVP, Visual C# My Articles

[Dylan van Heerden]

Thanks it works. All I had to do is add the - 1 for (int i = MdiChildren.Length - 1; i >= 0; i--) { Form f = MdiChildren[i]; f.Close(); } The Author of the book I'm reading should revise his book. ;) My brain is 2 small for all the knowledge that I need.

[LongRange Shooter]

You were real close, here is my CloseAllChildren process for my MDIParent:

	private void CloseAllChildren()
	{
		System.Windows.Forms.Form\[\] myChildren = this.MdiChildren;
		foreach (Form child in myChildren)
		{
			child.Close();
		}
		return;
	}

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