Specified element is already the logical child of another element. Disconnect it first

c# wpf frameworkelement
Guillaume Slashy picture Guillaume Slashy · Feb 2, 2012 · Viewed 37.5k times · Source

here is the error I have when I want to attach a FrameworkElement to a new Window to publish it to a PNG file.

So my idea is to remove the parent-child link, call my method, and add the child again with this code :

this.RemoveLogicalChild(element);
PublishFrameworkElement(element, stream);
this.AddLogicalChild(element);

But I got the exact same error...

I looked a lot of questions about this error, here on SO, but none answered to my problem What am I missing ?

EDIT : here is the code that worked for me :

var element = _GeneratedContent as FrameworkElement;
var ParentPanelCollection = (element.Parent as Panel).Children as UIElementCollection;
ParentPanelCollection.Clear();

FileStream stream = [...]

if (element != null)
{
    PublishFrameworkElement(element, stream);
    ParentPanelCollection.Add(element);
}
stream.Close();

Answer

Clemens picture Clemens · Feb 2, 2012

If element is the child of a Panel (e.g. Grid) you have to remove it from the Panel's Children collection. If it is set as Content of a ContentControl, you'd have to set that Content to null (or anything else that is not element).

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