dotnet/wpf · error · ArgumentException

SR.Automation_InvalidSynchronizedInputType

Error message

SR.Automation_InvalidSynchronizedInputType

What it means

SynchronizedInputAdaptor.StartListening validates that the SynchronizedInputType requested is one of the five supported values (KeyUp, MouseLeftButtonDown/Up, MouseRightButtonDown/Up). Any other value throws ArgumentException with SR.Automation_InvalidSynchronizedInputType naming the bad inputType.

Solutions

  1. Pass only SynchronizedInputType.KeyUp/KeyDown/MouseLeftButtonDown/MouseLeftButtonUp/MouseRightButtonDown/MouseRightButtonUp values supported by the API.
  2. Validate with Enum.IsDefined(typeof(SynchronizedInputType), value) before calling StartListening.
  3. Fix casts of raw integers to SynchronizedInputType in client or wrapper code.
  4. Rebuild/re-reference matching UIAutomationClient and PresentationCore versions.

Example fix

// before
provider.StartListening((SynchronizedInputType)42);
// after
var type = SynchronizedInputType.MouseLeftButtonUp;
if (Enum.IsDefined(typeof(SynchronizedInputType), type))
{
    provider.StartListening(type);
}
Defensive patterns

Strategy: validation

Validate before calling

SynchronizedInputType[] valid =
{
    SynchronizedInputType.KeyUp, SynchronizedInputType.MouseLeftButtonDown,
    SynchronizedInputType.MouseLeftButtonUp, SynchronizedInputType.MouseRightButtonDown,
    SynchronizedInputType.MouseRightButtonUp
};
if (!valid.Contains(inputType)) return;

Type guard

bool IsValidSynchronizedInputType(SynchronizedInputType t) =>
    t is SynchronizedInputType.KeyUp or SynchronizedInputType.MouseLeftButtonDown
       or SynchronizedInputType.MouseLeftButtonUp or SynchronizedInputType.MouseRightButtonDown
       or SynchronizedInputType.MouseRightButtonUp;

Try / catch

try
{
    provider.StartListening(inputType);
}
catch (ArgumentException ex)
{
    // invalid SynchronizedInputType; correct the enum value
}

Prevention

When it happens

Trigger: Calling ISynchronizedInputProvider.StartListening with a SynchronizedInputType value outside the supported set — e.g. default(SynchronizedInputType), an out-of-range cast, or an enum member added in a different framework version.

Common situations: UIA clients (or test code) passing a raw int cast to SynchronizedInputType; custom providers forwarding client-supplied enum values without validation; version mismatch between client pattern definition and WPF implementation.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/27f98d069852eef2. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationCore/MS/internal/Automation/SynchronizedInputAdaptor.cs:38

        internal SynchronizedInputAdaptor(DependencyObject owner)
        {
            Invariant.Assert(owner != null);
            _owner = owner;
        }
        /// <summary>
        /// This method is called by automation framework to trigger synchronized input processing.  
        /// </summary>
        /// <param name="inputType"> Synchronized input type</param>
        void ISynchronizedInputProvider.StartListening(SynchronizedInputType inputType)
        {
            if (inputType != SynchronizedInputType.KeyDown &&
                inputType != SynchronizedInputType.KeyUp &&
                inputType != SynchronizedInputType.MouseLeftButtonDown &&
                inputType != SynchronizedInputType.MouseLeftButtonUp &&
                inputType != SynchronizedInputType.MouseRightButtonDown &&
                inputType != SynchronizedInputType.MouseRightButtonUp)
            {
                throw new ArgumentException(SR.Format(SR.Automation_InvalidSynchronizedInputType, inputType));
            }
            
            UIElement e = _owner as UIElement;
            if (e != null)
            {
                if (!e.StartListeningSynchronizedInput(inputType))
                {
                    throw new InvalidOperationException(SR.Automation_RecursivePublicCall);
                }
            }
            else
            {
                ContentElement ce = _owner as ContentElement;
                if (ce != null)
                {
                    if (!ce.StartListeningSynchronizedInput(inputType))
                    {
                        throw new InvalidOperationException(SR.Automation_RecursivePublicCall);

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