Metro Style App Main(…)

If you have created a C# or C++ console application, you would be familiar with main(…) method which is the starting point of the console application.

    class Program
    {
        static void Main(string[] args)
        {
        }
    }
int _tmain(int argc, _TCHAR* argv[])
{
	return 0;
}

In a metro style app (Metro AG, I hope you don’t mind), the starting point for developer is App.OnLaunched(…).

        /// <summary>
        /// Invoked when the application is launched normally by the end user.  Other entry points
        /// will be used when the application is launched to open a specific file, to display
        /// search results, and so forth.
        /// </summary>
        /// <param name="args">Details about the launch request and process.</param>
        protected override void OnLaunched(LaunchActivatedEventArgs args)
        {
            Frame rootFrame = Window.Current.Content as Frame;

            // Do not repeat app initialization when the Window already has content,
            // just ensure that the window is active
            if (rootFrame == null)
            {
                // Create a Frame to act as the navigation context and navigate to the first page
                rootFrame = new Frame();

                if (args.PreviousExecutionState == ApplicationExecutionState.Terminated)
                {
                    //TODO: Load state from previously suspended application
                }

                // Place the frame in the current Window
                Window.Current.Content = rootFrame;
            }

            if (rootFrame.Content == null)
            {
                // When the navigation stack isn't restored navigate to the first page,
                // configuring the new page by passing required information as a navigation
                // parameter
                if (!rootFrame.Navigate(typeof(MainPage), args.Arguments))
                {
                    throw new Exception("Failed to create initial page");
                }
            }
            // Ensure the current window is active
            Window.Current.Activate();
        }

However, if you click show all files button which make the Visual Studio to show all hidden files, you will see a file \obj\Debug\App.g.i.cs.

image

image

Surprisingly, you will see the familiar static class Program and a method Main(string[] args). The main method actually starts the metro style app by initiate App instance. Don’t believe me? Try putting break point in there. Smile

    public static class Program
    {
        [global::System.CodeDom.Compiler.GeneratedCodeAttribute("Microsoft.Windows.UI.Xaml.Build.Tasks"," 4.0.0.0")]
        [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
        static void Main(string[] args)
        {
            global::Windows.UI.Xaml.Application.Start((p) => new App());
        }
    }
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