Visual-Studio/XCode Interface Builder, C Sharp App not relaunching its window

Question

Hello,
i've programmed my first C# App with Visual-Studio and XCode Interface Builder on my Mac.
The app is running fine except 1 large problem.

After starting the app everything is running fine, i am able to minimize or maximize it, but if
i close the window of the program (red cross top left) i am not able to relaunch the window of the app.
On Macbooks apps dont really close and still are running after closing the window, if you click on every
other app in your dock, which is still running, the window of this program will reappear.

Sadly this isnt the case for my app, the window remains hidden and to get the app running again if
have to rightlick on it in the dock and force it to quit and restart it afterwards.
After restarting the window reappears and everything is working fine until i close the window again.

-------

I've tried the app in debug mode and also in release mode.
The app is correctly signed with my developer key.

I use an Apple M1 Pro and Visual Studio for Mac 17.4.1 and XCode 14.1.

Answer 1

Hello @Alexander Zühr ,

You are using Xamarin.Mac to build a Mac app, macOS uses Mutiple Document Interface and this is the behavior of macOS.
You can use the native macOS API handler applicationShouldHandleReopen:hasVisibleWindows: method to reopen the closed window.

**Override the NSApplicationDelegate in AppDelegate.cs **

public override bool ApplicationShouldHandleReopen(NSApplication sender, bool hasVisibleWindows)  
      {  
            if (!hasVisibleWindows){  
                  var sb = NSStoryboard.FromName("Main", null);//Main.storyboard  
                  var controller = sb.InstantiateControllerWithIdentifier("MainWindow") as NSWindowController;// "MainWindow" is the Storyboard ID in WindowController of Main.storyboard.   
            controller.Window.MakeKeyAndOrderFront(this);//You can change this window(controller.Window) if you have another window in your project  
            }  
        return true;  
    }  

Tips: The Storyboard ID is empty by default in WindowController of Main.storyboard, you can set one, refer to the screenshot at Windows in Xamarin.Mac - Xamarin | Microsoft Learn

Best Regards,
Wenyan Zhang

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