NumericTextBoxBehavior for XAML-based Windows Store Applications

One of the first (and arguably most useful) behaviors that I wrote for MVVMHelpers was a NumericTextBoxBehavior.  This is a WPF behavior that restricts the input for a TextBox to be numeric-only.  Recently, someone emailed me asking if it was possible to do the same thing in a Windows Store application.  It absolutely is, but there are some caveats. My original implementation for WPF utilizes preview events - these are events which are sent to the ancestors of the element prior to it receiving a … [Read more...]

Blend Behaviors in Styles: DragPositionBehavior

In the last post, I referred to the DragPositionBehavior in the JulMar MVVM library.  This behavior allows any UIElement to be dragged and repositioned using the mouse without requiring any code logic on your part.  It’s easy to apply – using the traditional Blend syntax (easiest done by dragging the behavior onto an element):     <Interactivity:Interaction.Behaviors>         <julmar:DragPositionBehavior /> … [Read more...]

Correcting the WPF Themes

I'm a big fan of themes in WPF -- and I think it's great that Microsoft has released a whole set of themes for Silverlight and WPF at However, in using some of those themes, I've run into an annoying bug in the RadioButton template - specifically, the checked state doesn't always show up initially.  Looking at the template, it turns out to be an easy fix.  The "CheckIcon" is set to an opacity of zero initially (so it's not shown) and then a trigger is used to apply … [Read more...]