[BUG] "Handler not found for view SkiaSharp.Views.Maui.Controls.SKGLView."

[ToolmakerSteve]

Description

Target Windows Machine, get Unhandled Exception:

"Handler not found for view SkiaSharp.Views.Maui.Controls.SKGLView."

-- Other details --

.csproj targetframework: net8.0-windows10.0.19041.0

VS Community 17.9.7 on Windows 11 Home

Tested with Microsoft.Maui.Controls 8.0.40 +

SkiaSharp.Views & SkiaSharp.Views.Maui Controls:

• latest stable 2.88.8, then tried

• latest preview 3.0.0-preview.3.1

• Did not try on earlier versions of Maui or these SkiaSharp nugets.

• Before Maui, we used OpenTK.GLWpfControl with SkiaSharp.Views.WPF under .Net Framework. That older version of our app builds and runs on this PC without problems.

Code

Maui App template. Modified to add SKGLView. Removed AppShell and other unneeded stuff.

ToolmakerSteve/MauiAppWithSKGLView

        public MainPage()
        {
            InitializeComponent();

            MainThread.BeginInvokeOnMainThread(async () =>
            {
                await Task.Delay(2000);
                // UNCOMMENT these lines to test adding SKGLView in code.
                //var skv = new SKGLView() { WidthRequest = 300, HeightRequest = 300 };
                // Below line: Exception: "Handler not found for view SkiaSharp.Views.Maui.Controls.SKGLView."
                //layout.Children.Add(skv);
            });
        }

You can also share some XAML:

<ContentPage
    xmlns:sk="clr-namespace:SkiaSharp.Views.Maui.Controls;assembly=SkiaSharp.Views.Maui.Controls"
    ...

    <VerticalStackLayout x:Name="layout" Padding="30,0" Spacing="25">
        <!-- Exception: "Handler not found for view SkiaSharp.Views.Maui.Controls.SKGLView."  -->
        <sk:SKGLView WidthRequest="500" HeightRequest="300" BackgroundColor="Green" />
    </VerticalStackLayout>

Expected Behavior

A Window containing an SKGLView.

Actual Behavior

Unhandled Exception:

"Handler not found for view SkiaSharp.Views.Maui.Controls.SKGLView."

Version of SkiaSharp

Other (Please indicate in the description)

Last Known Good Version of SkiaSharp

Other (Please indicate in the description)

IDE / Editor

Visual Studio (Windows)

Platform / Operating System

Windows

Platform / Operating System Version

Windows 11 Home.

Did not test elsewhere.

Devices

No response

Relevant Screenshots

No response

Relevant Log Output

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[mattleibow]

I downloaded your sample and noticed the .UseSkiaSharp() line is missing from your MauiProgram.cs:

[daltzctr]

Nevermind. Needs preview version to work

[ToolmakerSteve]

I downloaded your sample and noticed the .UseSkiaSharp() line is missing from your MauiProgram.cs:

That fixes it. I completely forgot about that.

Sorry about the false alarm.

Hopefully this will help others who make a similar mistake.

[mattleibow]

I need to put this in the docs... Not sure if there are any docs for setting up a maui with skia app.

[tmijieux]

Indeed the latest stable nuget 2.88.8 still has this problem (as we can see in the source code
https://github.com/mono/SkiaSharp/blob/release/2.88.8/source/SkiaSharp.Views.Maui/SkiaSharp.Views.Maui.Controls/AppHostBuilderExtensions.cs#L25
)
I currently had to switch the UseSkiaSharp(bool)overload with true argument if i wanted it to work on ios with latest nuget(2.88.8) version (from Compatibility Nuget i guess?)

the doc i found on this was that:
https://learn.microsoft.com/en-us/dotnet/maui/migration/skiasharp?view=net-maui-8.0#initialize-skiasharp
(as i was migrating from a xamarin application, this is what I naturally found)

This thing is , i think the doc will be ok by the time you release the next version...

(one thing i dont understand is why i had no problem on android)