Common mistakes

Common mistakes

Table 12.3 lists the mistakes most often made when moving from Windows Forms to WPF.

Table 12.3. Common mistakes in WPF applications

Problem	Cause	Fix
elements overlap each other in a Grid	Grid.Row, Grid.Column are not set (all in cell 0,0)	set the attached properties or use a StackPanel
after resizing the window, part of the form is clipped or empty	fixed Width, Height, Margin from the designer, a Canvas for the form	a Grid with Auto and *, MinWidth, SizeToContent
a MouseDown handler on a panel does not fire after a button click	the button marked the event as handled	Click, PreviewMouseDown, or AddHandler(…, true)
XamlParseException at startup	an error in an attribute, a resource not found, the file does not have the Resource build action	read the InnerException, check the key and the Build Action
error WPF0001 during build	ThemeMode in code is an experimental API	#pragma warning disable WPF0001 or NoWarn
the code-behind grows, elements are looked up by name	UI logic and data logic are mixed	data binding and the MVVM pattern (Topic 13)