dotnet/wpf · error · ElementNotEnabledException

new ElementNotEnabledException()

Error message

new ElementNotEnabledException()

What it means

RangeValuePattern.SetValue first checks the element's IsEnabled property; if the element reports disabled, it throws ElementNotEnabledException. The pattern deliberately tests Enabled before the more general read-only check so callers get the most specific error.

Solutions

  1. Before SetValue, read AutomationElement.IsEnabledProperty (or TryGetCurrentPropertyValue) and skip/enable the control first
  2. Wait for the element to become enabled (poll or automation event on IsEnabledProperty/property-changed events)
  3. Catch ElementNotEnabledException around SetValue and surface a clear failure to the test/user
  4. Re-acquire the pattern/element; stale cached state can report incorrect enabled values

Example fix

// before
rangePattern.SetValue(10); // ElementNotEnabledException if disabled
// after
if (element.TryGetCurrentPropertyValue(AutomationElement.IsEnabledProperty, out var enabled) && (bool)enabled)
{
    rangePattern.SetValue(10);
}
Defensive patterns

Strategy: try-catch

Validate before calling

bool isEnabled = element.TryGetCurrentPropertyValue(AutomationElement.IsEnabledProperty, out var en) && en is bool b && b;
if (!isEnabled) return; // skip or wait until enabled

Type guard

bool IsEnabled(AutomationElement e) => e.TryGetCurrentPropertyValue(AutomationElement.IsEnabledProperty, out var v) && v is bool b && b;

Try / catch

try { rangePattern.SetValue(value); } catch (ElementNotEnabledException) { /* wait for enablement or abort step */ }

Prevention

When it happens

Trigger: Calling SetValue on a RangeValuePattern whose automation element is disabled (IsEnabledProperty false): e.g. a slider/spinner disabled in the UI, a window disabled/modally blocked, or an invalid-state control.

Common situations: Automating UI where the target control is disabled until a preceding step completes; test automation racing with app initialization; interacting with controls in disabled dialogs.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/6c59a5946f34360e. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/UIAutomation/UIAutomationClient/System/Windows/Automation/RangeValuePattern.cs:91

        //------------------------------------------------------
        //
        //  Public Methods
        //
        //------------------------------------------------------
 
        #region Public Methods
        /// <summary>
        /// Request to set the value that this UI element is representing
        /// </summary>
        /// <param name="value">Value to set the UI to, as a double</param>
        public void SetValue(double value)
        {
            // Test the Enabled state prior to the more general Read-Only state.            
            object enabled = _el.GetCurrentPropertyValue(AutomationElementIdentifiers.IsEnabledProperty);
            if (enabled is bool && !(bool)enabled)
            {
                throw new ElementNotEnabledException();
            }

            // Test the Read-Only state after the more specific Enabled state.
            object readOnly = _el.GetCurrentPropertyValue(IsReadOnlyProperty);
            if (readOnly is bool && (bool)readOnly)
            {
                throw new InvalidOperationException(SR.ValueReadonly);
            }
            UiaCoreApi.RangeValuePattern_SetValue(_hPattern, value);
        }

        #endregion Public Methods


        //------------------------------------------------------
        //
        //  Public Properties
        //

View on GitHub (pinned to 81131a70a4)