unoplatform/uno · error · XamlObjectWriterException

Unresolved object reference '{0}' was found

Error message

Unresolved object reference '{0}' was found

What it means

Thrown in ResolvePendingReferences (run at the end of writing) when an x:Reference name could not be resolved from either the name scope or the IXamlNameResolver. Forward/back references that remain unresolved at write completion surface here.

Source

Thrown at src/SourceGenerators/System.Xaml/System.Xaml/XamlObjectWriter.cs:604

		}

		internal IXamlNameResolver name_resolver {
			get { return (IXamlNameResolver) service_provider.GetService (typeof (IXamlNameResolver)); }
		}

		internal override IAmbientProvider AmbientProvider {
			get { return ambient_provider; }
		}

		void ResolvePendingReferences ()
		{
			foreach (var fixup in pending_name_references) {
				foreach (var name in fixup.Names) {
					bool isFullyInitialized;
					// FIXME: sort out relationship between name_scope and name_resolver. (unify to name_resolver, probably)
					var obj = name_scope.FindName (name) ?? name_resolver.Resolve (name, out isFullyInitialized);
					if (obj == null)
						throw new XamlObjectWriterException (String.Format (CultureInfo.InvariantCulture, "Unresolved object reference '{0}' was found", name));
					if (!AddToCollectionIfAppropriate (fixup.ParentType, fixup.ParentMember, fixup.ParentValue, obj, null)) // FIXME: is keyObj always null?
						SetValue (fixup.ParentMember, fixup.ParentValue, obj);
				}
			}
		}
		
		void HandleBeginInit (object value)
		{
			var si = value as ISupportInitialize;
			if (si == null)
				return;
			si.BeginInit ();
			source.OnAfterBeginInit (value);
		}
		
		void HandleEndInit (object value)
		{
			var si = value as ISupportInitialize;

View on GitHub (pinned to 0418340488)

Solutions

1. Ensure an element with `x:Name="<the name>"` exists in a scope visible to the resolver.
2. Fix typos in the x:Reference Member value.
3. If it is a forward reference, confirm the name resolver supports late resolution and that the name is truly in scope.

Example fix

<!-- before -->
<CheckBox IsChecked="{x:Reference Missing}" />
<!-- after -->
<CheckBox x:Name="cb" IsChecked="{x:Reference cb}" />

// Before finishing, verify every x:Reference target has a matching x:Name in scope.
foreach (var name in referencedNames)
    if (nameScope.FindName(name) == null)
        throw new InvalidOperationException($"x:Reference target '{name}' is not defined.");

try { /* write/load the full graph */ }
catch (XamlObjectWriterException ex) when (ex.Message.Contains("Unresolved object reference")) {
    // a referenced name is missing or out of scope; add/fix x:Name.
}

When it happens

Trigger: XAML containing `<x:Reference Member="MissingName"/>` where no element has `x:Name="MissingName"` in any visible scope.

Common situations: Typo in the referenced name; forward reference to a name defined in a sibling/nested scope not visible to the resolver; missing x:Name on the target element.

Related errors

• serviceProvider does not implement IXamlNameResolver
• Member '{0}' is already written to current type '{1}'
• RootObjectInstance type '{0}' is not assignable to '{1}'
• The value for '{0}' property is null
• An error occurred on getting provided value

AI-assisted analysis of unoplatform/uno@0418340488 (2026-08-13). Data as JSON: /api/errors/a20365b66c7d3b5d. Report an issue: GitHub.