Qml.Net: A new C# library for cross-platform .NET GUI development

Qml.Net is a C# library for cross-platform GUI development with native dependency. It exposes the required object types to host a QML engine. In Qml.NET, Qml and JavaScript together form the UI layer. It can be thought of as the view in MVC.

Qml.Net features

The PInvoke code in this .NET library is hand-crafted by developer Paul Knopf to ensure appropriate memory management and pointer ownership semantics. He is pretty confident about the library and mentions in his blog “I’d bet you couldn’t generate a segfault, even if you wanted to.”

In Qml.Net C# objects can be registered to be treated as QML components. You can then interoperate with them as you would with regular JavaScript objects. The registered C# objects serve as a portal through which the QML world can interact with your .NET objects.

This has an added benefit of keeping your business/UI concerns separate cleanly. There will also be no chatty PInvoke calls for rendering. It is a great match.

A pre-compiled portable installation of Qt and the native C wrapper is available for Windows, OSX, and Linux. Developers wouldn’t have to bother with C/C++. All you need to know is QML, C#, and JavaScript; QML if fairly simple.

QML can’t really be classified as a language, in the semantic sense. More appropriately it can be considered as a combination of JSON and JavaScript.

Qml.Net support and working

Qml.Net will work with any .NET language including popular C# and functional languages like F#. Your libraries will reference the pure .NET NuGet package, Qml.Net. The host process (Program.Main) references the native NuGet packages. This is dependent on the OS you are on:

Qml.Net.WindowsBinaries
Qml.Net.OSXBinaries
Qml.Net.LinuxBinaries

Paul currently only tests his own models that are C# objects registered with the QML engine. They are specific to each control/page.

Since Microsoft's announcement of .NET Core, there hasn’t been any clear idea on cross-platform GUI development. Although Microsoft plans to support WPF in .NET Core 3.0, it will be limited to Windows machines.

With community involvement and support, Qml.net can be a potential game changer. You can head to the GitHub repository and also view some hosted examples to get a better idea.

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