Modify a code-behind file
To edit a code-behind file in a Microsoft Expression Blend project, you can double-click the file name in the Projects panel.
If the file is a code-behind file written in C# or Visual Basic .NET, the file will open in the Expression Blend code editor. The code editor includes find-and-replace functionality and IntelliSense.
If you have Microsoft Visual Studio 2008 installed, you can optionally open the code-behind file in Visual Studio.
For more information about working with code in Expression Blend applications, see Visual design compared to writing XAML and code, Debug Expression Blend applications in Visual Studio 2008, and Writing code that will respond to events.
In Expression Blend, in the Projects panel, expand the node for your document (for example, MainWindow.xaml) to see the code-behind file.
Right-click the code-behind file, and then click Edit in Visual Studio.
When you open a single code-behind file in Visual Studio instead of opening the entire project and then the file, you cannot use the auto-complete, Build, and Debug features of Visual Studio.