dotnet/wpf · error · InvalidOperationException

Storyboard_NameNotFound

Storyboard_NameNotFound

Error message

SR.Format(SR.Storyboard_NameNotFound, targetName, nameScopeUsed.GetType().ToString())

What it means

After finding the name scope in which to search, ResolveTargetName looks up TargetName; if the name is not registered in that scope (FindName returns null), WPF throws this InvalidOperationException including the target name and the type of the name scope searched.

Solutions

Ensure the TargetName exactly matches the x:Name of an element in the same name scope as the storyboard.
Move the storyboard into the same template/visual tree as its target element.
Use Storyboard.Target instead of TargetName when you already hold the DependencyObject reference in code.
Delay storyboard start (e.g. on Loaded event) until named elements exist.

Example fix

// before
<Storyboard>
  <DoubleAnimation Storyboard.TargetName="Rect1" .../> <!-- Rect1 not in this scope -->
</Storyboard>

// after
<Grid>
  <Rectangle x:Name="Rect1"/>
  <Storyboard x:Key="sb">
    <DoubleAnimation Storyboard.TargetName="Rect1" .../>
  </Storyboard>
</Grid>

Defensive patterns

Strategy: validation

Validate before calling

bool ok = targetElement.FindName("Rect1") != null; // resolve before starting

Type guard

static bool NameResolvable(FrameworkElement scope, string name) => scope?.FindName(name) != null;

Try / catch

try { storyboard.Begin(fe, true); } catch (InvalidOperationException ex) when (ex.Message.Contains("name")) { log.Error($"Storyboard target name missing: {ex.Message}", ex); }

Prevention

Keep storyboards in the same scope as their TargetName elements
Spell-check TargetName against x:Name declarations
Start storyboards on Loaded when all named elements exist
Prefer Storyboard.Target with direct references in code

When it happens

Trigger: Setting Storyboard.TargetName to a name that does not exist in the resolved name scope — e.g. targeting an element in another template, a different x:Name, or an object registered after resolution runs.

Common situations: Storyboard defined in App.xaml or a shared template targeting a page-local element; typos in TargetName; elements loaded dynamically after the storyboard starts; names inside DataTemplate items that are virtualized.

Understand the failure class

Background: "Not found" and "does not exist" errors: why "Task not found", "No such folder", and "Can't find" fire when a lookup comes back empty — this error's family across 14 libraries.

Related errors

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/d83022551b75383a. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Media/Animation/Storyboard.cs:276

                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;
    }

    /// <summary>
    ///     Finds a BeginStoryboard with the given name, following the rules
    /// governing Storyboard.  Returns null if not found.
    /// </summary>
    /// <remarks>
    ///     If a name scope is given, look there and nowhere else.  In the

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