Many of you have probably used Telerik's TreeView or going to do so in the future. One of its many features is the TriStateMode. In this blog post I'm going to explain how TriStateMode mode is designed to work and propagate the values up and down the tree. When in TriStateMode (IsTriStateMode=”True”) checking/unchecking an item makes the TreeView propagate the value. The value propagation actually checks/unchecks all items’ children and updates the chain of parents with appropriate value (checked, unchecked or undetermined). CheckState vs. IsChecked The TreeView exposes two properties used to manipulate items' check state - CheckState (of type ToggleState) and IsChecked...

With Q3 2010 we introduced some cool UI additions to RadRichTextBox, including SelectionMiniToolBar and ContextMenu. SelectionMiniToolBar SelectionMiniToolBar is a floating toolbar that appears next to the current position after making a selection with the mouse in the document. It contains some useful commands for formatting text: As RadRichTextBox loads the default SelectionMiniToolBar using MEF, it can be completely replaced with a custom one. This can be done as easy as with the other RadRichTextBox dialogs by implementing the ISelectionMiniToolBar interface and marking the class that implements it with the CustomSelectionMiniToolBarAttribute attribute. The technique was also described in greater details in this blog...

The latest release of Silverlight - ver.4 was released earlier this year. For me this was the first Silverlight release that was stable and mature enough so that I could recommend to anyone building business applications to use it broadly. Now, six months later, we can see that the Silverlight adoption is very high and that there are a lot of great tools built with it. Regardless of all the recent comments and mostly speculations about the future of Silverlight I believe that this will be the primary MS platform for building applications for Windows and Mac in years to come. At MIX this year, the Silverlight platform was also introduced to...

The Big UI Problem Since the User Interface came on the scene of software development, it is constantly one of the biggest problems. It is really hard to design the architecture of the User Interfaces, User Interactions and deal with all the logic around, all the different states and behaviors. It is not an easy task also to separate the UI logic from the other layers of the architecture. On the other hand, even if you develop the whole application, you should start to think about how to automatically test the UI (unit tests, components tests, integration tests…), how to maintain it in a way...

Telerik's official Q3 2010 release just came public introducing many improvements and new features. One of them is RadMediaPlayer's full screen support. Prior to Q3 2010 release developers had to implement additional logic to provide full screen support for their apps using RadMediaPlayer. With the new release users can experience true full screen apps without any custom code. Full screen support is build inside the media player but can be easily customized by using the IsFullScreenProperty or attaching a handler to the FullScreenChanged event. In addition, two new properties are available which you can use to customize whether the video controls panel and...