dotnet/maui · error · XamlParseException

Unable to find a TragetType for the Bindable Property. Try p

Error message

Unable to find a TragetType for the Bindable Property. Try prefixing it with the TargetType.

What it means

Catch-all XamlParseException raised at the end of FindTypeForVisualState when no ancestor in the visual-state parent chain exposed a TargetType (neither a TriggerBase nor a Style). The converter exhausted parents[5] for a Trigger or Style and found neither, so it cannot infer which type the BindableProperty belongs to. Note the message contains a typo ('TragetType') which is preserved in source.

Source

Thrown at src/Controls/src/Core/BindablePropertyConverter.cs:158

				return vsTarget.GetType();

			if (parents[3] is not VisualStateGroupList)
				throw new XamlParseException($"Expected {nameof(VisualStateGroupList)} but found {parents[3]}.", lineInfo);

			if (parents[4] is VisualElement veTarget)
				return veTarget.GetType();

			if (parents[4] is not Setter)
				throw new XamlParseException($"Expected {nameof(Setter)} but found {parents[4]}.", lineInfo);

			if (parents[5] is TriggerBase trigger)
				return trigger.TargetType;

			// These must be part of a Style; verify that 
			if (parents[5] is Style style)
				return style.TargetType;

			throw new XamlParseException($"Unable to find a TragetType for the Bindable Property. Try prefixing it with the TargetType.", lineInfo);

		}

		public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
		{
			if (value is not BindableProperty bp)
				throw new NotSupportedException();
			return $"{bp.DeclaringType.Name}.{bp.PropertyName}";
		}
	}
}

View on GitHub (pinned to f377ff1c5e)

Solutions

1. Prefix the property with its owner type, e.g. Property="VisualElement.BackgroundColor", so the converter does not need parent inference.
2. Ensure the enclosing Style has a TargetType set.
3. Move the visual-state Setter back under a proper Style or Trigger.

Example fix

<!-- before -->
<Style><!-- missing TargetType -->
  ...
  <Setter Property="BackgroundColor" Value="Red" />
</Style>

<!-- after -->
<Style TargetType="VisualElement">
  ...
  <Setter Property="VisualElement.BackgroundColor" Value="Red" />
</Style>

// Qualify the property with its owner type so parent inference is unnecessary:
// Property="VisualElement.BackgroundColor"

try { /* compile */ }
catch (XamlParseException ex) when (ex.Message.Contains("TragetType"))
{
    // note: message has a typo; guide author to qualify property or set TargetType
}

When it happens

Trigger: A visual-state Setter whose Style/Trigger parent chain is incomplete or whose Style lacks a TargetType; using visual states inside a custom container that is neither Style nor TriggerBase and provides no TargetType.

Common situations: A Style with no TargetType attribute; visual states nested under a non-Style, non-Trigger element; refactoring that detached the Setter from its Style.

Related errors

• Expected {nameof(VisualStateGroup)} but found {parents[2]}.
• Expected {nameof(VisualStateGroupList)} but found {parents[3
• Expected {nameof(Setter)} but found {parents[4]}.
• Can't resolve {0}
• Can't resolve {parts[0]}

AI-assisted analysis of dotnet/maui@f377ff1c5e (2026-08-13). Data as JSON: /api/errors/fc72d4b9a93f74ce. Report an issue: GitHub.