No Main() in WPF?

Main() is automatically provided by the CLR and the WPF.

The C# compiler takes a command-line switch /m which specifies the type that contains the implementation of Main(). By convention, if no startup object is explicitly specified, the CLR will lookup any class that has a static Main() method and will call it. (As @Marc Gravel pointed out in his comment)

In the case of WPF, the Main() is automatically generated when App.xaml is built and the /m switch is specified to make the C# compiler use that class as entry point. If you look at the project properties however, you'll find there's a setting for you to choose the startup object. So if you want, you can provide your own class that implements Main().

Note that this will put the responsibility on you to create the Application instance and call its Run() method to ensure that the WPF infrastructure is started properly.

It is generated during build, but you can provide your own (disambiguating it in project-properties as necessary). Look in obj/debug for an app file; I have (courtesy of "C# 2010 Express") App.g.i.cs with:

namespace WpfApplication1 {


    /// <summary>
    /// App
    /// </summary>
    [System.CodeDom.Compiler.GeneratedCodeAttribute("PresentationBuildTasks", "4.0.0.0")]
    public partial class App : System.Windows.Application {

        /// <summary>
        /// InitializeComponent
        /// </summary>
        [System.Diagnostics.DebuggerNonUserCodeAttribute()]
        public void InitializeComponent() {

            #line 4 "..\..\..\App.xaml"
            this.StartupUri = new System.Uri("MainWindow.xaml", System.UriKind.Relative);

            #line default
            #line hidden
        }

        /// <summary>
        /// Application Entry Point.
        /// </summary>
        [System.STAThreadAttribute()]
        [System.Diagnostics.DebuggerNonUserCodeAttribute()]
        public static void Main() {
            WpfApplication1.App app = new WpfApplication1.App();
            app.InitializeComponent();
            app.Run();
        }
    }
}

The Main() method is created automatically. If you want to provide your own you have to (tested in VS2013, VS2017 and VS2019):

• Right-click App.xaml in the solution explorer, select Properties
• Change 'Build Action' to 'Page' (initial value is 'ApplicationDefinition')

Then just add a Main() method to App.xaml.cs. It could be like this:

[STAThread]
public static void Main()
{
    var application = new App();
    application.InitializeComponent();
    application.Run();
}