Application.Run Method (Window)
Starts a Windows Presentation Foundation (WPF) application and opens the specified window.
public int Run(
Type: System.Int32The Int32 application exit code that is returned to the operating system when the application shuts down. By default, the exit code value is 0.
Run is called from a browser-hosted application (for example, an XAML browser application (XBAP)).
This overload extends the Run method to open the specified window after an application starts running.
If you define a code Application that opens a window when it starts running, you explicitly call Run.
If you create your Application using markup, or markup and code-behind, you can automatically open a window during using either of the following techniques:
The following example shows an application with a manually-created static entry point method that instantiates Application, before calling Run.
public class EntryPoint
// All WPF applications should execute on a single-threaded apartment (STA) thread
public static void Main()
Application app = new Application();
Supported in: 4, 3.5, 3.0
.NET Framework Client Profile
Supported in: 4, 3.5 SP1
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.