View your design or the XAML that defines your design
You can change the artboard to show the visual design of your XAML document or the XAML markup that describes your visual design. Alternatively, you can display both.
Design view Changes the artboard to Design view, the visual design view of your document. In this view, you can use the tools from the Tools panel to draw or modify objects on the artboard, view the objects that make up your design in the Objects and Timeline panel, and view the Properties of selected objects.
XAML view Changes the artboard to XAML view. In this view, you can edit XAML code manually, and use XAML IntelliSense. You can go to a specific line or search for and replace text, just as you can in any text editor. However, in this view, you cannot use the tools in the Tools panel, view the tree of objects in the Objects and Timeline panel, or use the Properties panel to modify objects. Additionally, most menu items are disabled in this view.
Split view Changes the artboard to a panel layout that shows both Design and XAML views. In this view, all the Expression Blend tools and features are available as if Design view were selected, and when you select an object, the respective line of XAML is highlighted. You can further configure the panel layout in this view.
Code-behind files do not have different authoring views. For more information, see Modify a code-behind file.