Create reusable content
You can make elements on a screen into user controls that can be used in multiple pages throughout a prototype. For example, you can create a navigation bar, and then make the navigation bar into a user control so that you can reuse the control throughout your prototype.
For more information about creating UserControls, see Create an application flow.
You might also want to create a library of UserControls so that you can easily reuse them throughout multiple projects. You can create a Microsoft Silverlight or Windows Presentation Foundation (WPF) control library.
To create a new control library
On the File menu, click New Project, and then select either Silverlight or WPF.
If you create a Silverlight project, click Silverlight Control Library. If you create a WPF project, click WPF Control Library.
In the Name box, type a name for the project.
In the Location box, type the name of or browse to the folder where you want to store the project. By default, this is a folder named "Blend Projects" in your "My Documents" folder.
On the Language menu, select a programming language (Visual C# or Visual Basic).
For more information about creating projects in Expression Blend, see Create a new project.
Now that you have created a new control library, you can create new user controls to include in the library. Create any new user controls that you want for your project.
For more information about creating new user controls, see Create a new user control in your project.
After you have created the user controls that you want to include in your control library, build the project by clicking CTRL+SHIFT+B.
For more information, see Build a project.
Now that you have created and built your control library, you can add a reference to the library from inside your project, and reuse the controls from the library in your new project.
For more information, see Add or remove a reference.