Exploring Multi-window Apps in .NET MAUI Preview 11

This is post #2 in a series called ‘.NET MAUI Source of Truth’.

About Source Of Truth – As any developer knows, source code is the purest form of truth in working software. So I’ve decided the best way to get deep into .NET MAUI is to look at the source code.

In my last post we explored the .NET MAUI codebase learning about the new Windows functionality but we could not get experience with overlays until Preview11. The great news is that Preview11 has been shipped.

You can learn more about the preview here: https://devblogs.microsoft.com/dotnet/announcing-dotnet-maui-preview-11/

I’m doing all this on the mac. You can also do this on Windows but you’ll need a ipad. If you want to use your Mac you can, you can see some details on installing this on a mac, you can find more detailed installation and upgrade notes at these locations:

On another note the documentation for .NET doesn’t provide instructions to set your path for dotnet permanently. If you want to do this then following these instructions. I found dotnet located here: /usr/local/share/dotnet/dotnet. 

In my case I already had dotnet and maui installed, so I just needed to do an upgrade. At the time that I wrote this post then Maui Check was not upgrading me to Preview 11, but do note I did first run Maui Check and it resolved a few other issues for me so I would recommend doing a check first.

Here’s what I did.

1. Run Maui Check.

cd $HOME/.dotnet/tools

Then I resolve resolved all the issues associated

2. Manually update to preview11

sudo dotnet workload install maui
dotnet new --install Microsoft.Maui.Templates
dotnet new maui -n MauiPreview11Play
cd MauiPreview1Play
dotnet restore
dotnet build -t:Run -f net6.0-ios

Generally in .NET MAUI development(on the mac) I’ve been able to use Visual Studio Mac Preview, in this case I’ve updated to the latest version and now I can open the project.

Update: Initially I started with using VS MAC Preview but eventually it caused too many issues, not that I think this was a VS issue but more that .NET MAUI was not building and deploying without issues. Eventually I turned to VS Code the command line.

It took me a long time to get this working because I would have issues building and deploying, I was not able to tell if it was my issues or .NET MAUI. I had to switch between –no-incremental and a normal build when I had issues with build and deploy.

dotnet build --no-incremental -t:Run -f net6.0-maccatalyst / ios

dotnet build -t:Run -f net6.0-maccatalyst / ios


Once we have the new project running we can start our setup for Multi-window.

Step 1. Add a SceneDelegate, you can add this under Platforms/MacCatalyst and Platforms/iOS.

using Foundation;
using Microsoft.Maui;
using ObjCRuntime;
using UIKit;

namespace MauiPreview11Play;

public class SceneDelegate : MauiUISceneDelegate


Step 2. Update your info.plist to support multiple scenes. You can do this under /Platforms/iOS and /Platforms/MacCatalyst


Step 3. Setup the multi-window code. In this case I’ve just edited the existing files to add some buttons and methods.

    Text="Open window"
    SemanticProperties.Hint="open it"
    HorizontalOptions="Center" />

    Text="Close window"
    SemanticProperties.Hint="Close it"
    HorizontalOptions="Center" />

private void OpenWindow(object sender, EventArgs e)
	Application.Current.OpenWindow(new Window(new MainPage()))

In order to open a window we can use the OpenWindow method on the Application, providing a new Window.

private void CloseWindow(object sender, EventArgs e)
	var window = this.GetParentWindow();
	if (window is not null)

In order to close a window we need to provide the window.

Here’s a video of multiple windows in a maccatalst app

Also multiwindow in iPad.

There we go, .NET MAUI Multi-Windows Apps. If you want to see the code you can find it here: https://github.com/rid00z/NETMAUIMultiWindow


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