Question

Utter noob question on C# – in the code below, what does the line

UIWindow window; 

mean exactly and what is its relationship to the line

window = new UIWindow (UIScreen.MainScreen.Bounds);

Is “UIWindow window” some kind of variable declaration?

public partial class AppDelegate : UIApplicationDelegate
{
    UIWindow window;
    HelloWorld_iPhoneViewController viewController;

    /// <summary>
    /// This method is invoked when the application has loaded and is ready to run. In this 
    /// method you should instantiate the window, load the UI into it and then make the window
    /// visible.
    /// </summary>
    /// <remarks>
    /// You have 5 seconds to return from this method, or iOS will terminate your application.
    /// </remarks>
    public override bool FinishedLaunching (UIApplication app, NSDictionary options)
    {
        // create a new window instance based on the screen size
        window = new UIWindow (UIScreen.MainScreen.Bounds);


        viewController = new HelloWorld_iPhoneViewController ("HelloWorld_iPhoneViewController", null);
        window.RootViewController = viewController;
        window.MakeKeyAndVisible ();

        return true;
    }
}

Answer 1

This line of code declares a variable named window of the type UIWindow (the value of which is initially null):

UWindow window;

And this line assigns a value to the window variable:

window = new UIWindow (UIScreen.MainScreen.Bounds);