I’ve submitted my first application for Windows Phone! It is very simple app. Marketplace has a good amount of similar apps: Planning Poker. Anyway, I’ve wrote couple own behaviors for TextBox and want to share this code with you.

If you are Silverlight/WPF developer and have already used Blend than you should know what are Behaviors and Interactions. If not or if you forget what it is I will remind you. You can find these libraries in directory “c:\Program Files (x86)\Microsoft SDKs\Expression\Blend\” (in case if you have Windows x86 than you should remove from path (x86)). And of course these libraries exist only in case if Blend has been installed. In this directory you can find packs of libraries for WPF/Silverlight and WindowsPhone. If you don’t know what are Behaviors and Interaction I suggest you to read Expression Blend SDK for Windows Phone on MSDN. In few words: this is approach to extend default control’s features, more than! this approach allows you to use MVVM pattern.

Let’s extend some features of default TextBox control.

At previous my blog post I wrote about how to implement validation with DataAnnotations. I this part of my article I will describe interfaces IDataErrorInfoand INotifyDataErrorInfo. I recommend you to read first part before read this part. Because I use example from previous part.

Silverlight 4 has some new ways for validate input values (some new approaches to implement validation in your application). First approach is DataAnnotation. In this case you should describe validation rules with attributes. Two other ways (both of them is came with Silverlight 4) – you should implement one of interfaces for your ViewModel: IDataErrorInfo or INotifyDataErrorInfo. I want to talk about all of these approaches, about pros and cons of using each of them. Goal of this article to get a best way to implement validation of input values in my and your applications. This part of article about DataAnnotations.

Data export from DataGrid to Excel is very common task, and it can be solved with different ways, and chosen way depend on kind of app which you are design. If you are developing app for enterprise, and it will be installed on several computes, then you can to advance a claim (system requirements) with which your app will be work for client. Or customer will advance system requirements on which your app should work. In this case you can use COM for export (use infrastructure of Excel or OpenOffice). This approach will give you much more flexibility and give you possibility to use all features of Excel app. About this approach I’ll speak below. Other way – your app is for personal use, it can be installed on any home computer, in this case it is not good to ask user to install MS Office or OpenOffice just for using your app. In this way you can use foreign tools for export, or export to xml/html format which MS Office can read (this approach used by JIRA). But in this case will be more difficult to satisfy user tasks, like create document with landscape rotation and with defined fields for printing.

At this article I'll show you how to work with Excel object from .NET 4 and Silverlight 4 with dynamic objects and give you an approach which allow you to export data from DataGrid Silverlight and WPF controls.