dotnet/wpf · error · InvalidOperationException

Storyboard_NoNameScope

Storyboard_NoNameScope

Error message

SR.Format(SR.Storyboard_NoNameScope, targetName)

What it means

Storyboard.ResolveTargetName needs an INameScope (or FrameworkElement/FrameworkContentElement) in which to look up TargetName. If none is supplied, it throws this InvalidOperationException: a name can only be resolved within some name scope.

Solutions

Pass the FrameworkElement (or FrameworkContentElement) that contains the storyboard to Storyboard.Begin/Seek/etc.
Ensure TargetName resolution happens within the template/page that registered the target name.
Use the strongly typed overloads taking FrameworkElement instead of object.

Example fix

// before
storyboard.Begin((object)null, IsControllable); // no name scope

// after
storyboard.Begin(this /* containing FrameworkElement */, true);

Defensive patterns

Strategy: validation

Validate before calling

bool ok = containingElement != null; // FrameworkElement that owns the name scope

Type guard

static bool HasNameScope(FrameworkElement fe) => fe != null;

Try / catch

try { storyboard.Begin(fe, isControllable); } catch (InvalidOperationException ex) { log.Error("No name scope for TargetName resolution", ex); }

Prevention

Always pass the containing FrameworkElement to Storyboard control APIs
Avoid object-typed overloads with null
Start storyboards after the visual tree is loaded

When it happens

Trigger: Calling Storyboard APIs (e.g. Storyboard.Begin, Seek, targeting resolution during ClockTreeWalkRecursive/ApplyMediaClock) with a null nameScope on a path that passes neither a FrameworkElement nor FrameworkContentElement — typically invoking with (object) overloads with a null target element.

Common situations: Calling Storyboard.Begin(null) or controlling a storyboard with a null containingObject; using storyboard targeting APIs from code without specifying the element that defines the names.

Related errors

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/92776d98579a54b6. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Media/Animation/Storyboard.cs:270

            {
                namedObject = ((FrameworkTemplate)nameScope).FindName(targetName, fe);
                nameScopeUsed = nameScope;
            }
            else
            {
                namedObject = fe.FindName(targetName);
                nameScopeUsed = fe;
            }
        }
        else if( fce != null )
        {
            Debug.Assert( nameScope == null );
            namedObject = fce.FindName(targetName);
            nameScopeUsed = fce;
        }
        else
        {
            throw new InvalidOperationException(
                SR.Format(SR.Storyboard_NoNameScope, targetName));
        }

        if( namedObject == null )
        {
            throw new InvalidOperationException(
                SR.Format(SR.Storyboard_NameNotFound, targetName, nameScopeUsed.GetType().ToString()));
        }

        targetObject = namedObject as DependencyObject;
        if( targetObject == null )
        {
            throw new InvalidOperationException(SR.Format(SR.Storyboard_TargetNameNotDependencyObject, targetName ));
        }

        return targetObject;
    }

View on GitHub (pinned to 81131a70a4)