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Troubleshooting

This topic provides several tips on common questions or issues that you may encounter while using Actipro Avalonia UI controls.

Actipro Controls are Blank, Transparent or Missing Content

If a control does not appear the way it should (especially if it is blank), this can be caused by missing themes. Actipro Avalonia UI controls require the ModernTheme to be loaded for control templates and resources to be available for the controls.

If ModernTheme is loaded but controls from the ActiproSoftware.Controls.Avalonia.Pro NuGet package are still not rendering properly (like the Fundamentals product controls), make sure ModernTheme.Includes property includes the Pro controls.

See the "Using Actipro Themes" section of the Themes Getting Started topic for more details on loading the theme, including sample code.

Native Avalonia Controls Missing Actipro Themes

If native themes are missing for basic controls (like TextBox), make sure the ModernTheme is loaded since it defines the control templates and resources used for native controls.

If the ModernTheme is loaded but native controls are still not properly themed, verify that the ModernTheme is loaded after any other themes since the last loaded theme will override the themes defined before it. Also make sure that the ModernTheme.AreNativeControlThemesEnabled property is not set to false as this would prevent the themes from being loaded.

If basic native controls are themed and native ColorPicker or DataGrid are not, you may be missing a NuGet package and/or theme include setting.

  • Be sure to add a reference to the corresponding ActiproSoftware.Controls.Avalonia.Themes.ColorPicker and/or ActiproSoftware.Controls.Avalonia.Themes.DataGrid NuGet package to ensure control templates are available.
  • When loading ModernTheme, make sure the ModernTheme.Includes property defines the NativeColorPicker and/or NativeDataGrid controls.

See the "Using Actipro Themes" section of the Themes Getting Started topic for more details on loading the theme, including sample code.

Some String Resource Customizations Don't Take Effect in UI

If you run into a scenario where some string resource customizations do take effect in the UI but others don't, the problem is most likely the location of your string customization code.

As indicated by a note in the Customizing String Resources topic, all string resources should be customized immediately at application startup (such as in Application.Initialize) and before any UI or control classes are even referenced. The note in the topic gives more detail on why this is necessary.

Data Binding Errors at Run-Time

Sometimes there may be some data binding errors that show up in the Visual Studio console window when executing an application that uses an Actipro Avalonia UI control product. Actipro Avalonia UI has some very large and complex templates for its products' controls and these error messages may show up in the Visual Studio console due to the timing between data binding resolution and visual tree creation.

It is very important to note that the data binding errors are NOT problems in our code. If they were, the bindings would not work at all at run-time and you would see broken UI functionality. This is not the case, everything works correctly at run-time after the visual tree has been fully constructed and the bindings have been re-evaluated. The Avalonia team plans on refactoring the data binding system in the future to prevent these misleading error messages from being logged.

So just to reiterate, the data binding error messages are not problems with our code, and are simple warnings due to data bindings trying to resolve themselves before the targets' visual trees are created. You may safely ignore these error messages.

Native AOT (Ahead-of-Time) Generates "No precompiled XAML found for avares:..." Error in Debugger

Applications that want to take advantage of Native AOT add the <PublishAot>true</PublishAot> setting to their project's properties. Adding this setting can lead to a runtime exception when executing the application if it hasn't been published with dotnet publish or an IDE's equivalent publish feature. This setting also enables trimming, which will attempt to remove unused code from the compiled application. Proper trimming requires the compiler to know which code is actually in use, and then can cause problems with dynamic code that cannot be statically analyzed.

The ModernTheme class used to enable Actipro Themes dynamically loads additional theme assets from other assemblies based on the value of the Includes property. While the class has been properly attributed to indicate its dependency on other assemblies and can be successfully published, compiled applications with PublishAot set to true that didn't also get published appear to have issues with the dynamic dependencies and will trim the theme resources anyway. This can result in an error message like the following when the ModernTheme is loaded within Application.Styles:

No precompiled XAML found for avares://ActiproSoftware.Avalonia.Fundamentals/Themes/Common.axaml (baseUri: ), make sure to specify x:Class and include your XAML file as AvaloniaResource

To resolve the issue, the application will need to explicitly reference the necessary styles to prevent them from being trimmed. The following shows how to redefine ModernTheme to explicitly include all the possible style resources:

<Application ...
	xmlns:actipro="http://schemas.actiprosoftware.com/avaloniaui"
	>
	<Application.Styles>
		...

		<actipro:ModernTheme>

			<!-- When using Native ColorPicker -->
			<StyleInclude Source="avares://ActiproSoftware.Avalonia.Themes.Native.ColorPicker/Themes/Common.axaml"/>

			<!-- When using Native DataGrid -->
			<StyleInclude Source="avares://ActiproSoftware.Avalonia.Themes.Native.DataGrid/Themes/Common.axaml"/>

			<!-- When using Pro components -->
			<StyleInclude Source="avares://ActiproSoftware.Avalonia.Fundamentals/Themes/Common.axaml"/>

		</actipro:ModernTheme>

	</Application.Styles>
</Application>

Basically, whichever resource was mentioned by the error message will need to be explicitly listed like shown above.

The ModernTheme.Includes property does not have to be defined when explicitly including the styles, and you should only include styles for the assemblies used by your application.

WebAssembly (WASM) Performance Issues

Avalonia UI supports running in the browser with WebAssembly. As of v11.0, the Avalonia UI framework documention is clear to indicate the functionality is not ready for production. During testing with Actipro Avalonia UI controls in a browser, you may notice less-than-desired performance compared to running natively. This is expected to improve with .NET 8.

Badge Adornments Aren't Clipped Properly

The Avalonia adorner system (last tested on v11.0.7) may not properly clip adornments based on the clip regions of ancestors of the adorned element. This can lead to possible scenarios where an adorned element might be scrolled out of view, but the badge adornment is still visible. The Badge topic has additional detail on this issue and offers a workaround if the problem is encountered.