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Fix InvalidCastException in Control.OnHandleDestroyed for non-ControlAccessibleObject #14295

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Fix InvalidCastException in Control.OnHandleDestroyed for non-ControlAccessibleObject #14295

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7bb70c5
Fix InvalidCastException in Control.OnHandleDestroyed for non-Control…
LeafShi1 Feb 12, 2026
4cb37bd
Add unit tests
LeafShi1 Feb 12, 2026
8aa399b
Removing extra blank line
LeafShi1 Feb 12, 2026
5d05194
Add assertion for test case "Control_OnHandleDestroyed_CustomAccessib…
LeafShi1 Feb 24, 2026
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8 changes: 5 additions & 3 deletions src/System.Windows.Forms/System/Windows/Forms/Control.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -7518,14 +7518,16 @@ protected virtual void OnHandleDestroyed(EventArgs e)
((EventHandler?)Events[s_handleDestroyedEvent])?.Invoke(this, e);

// The Accessibility Object for this Control
if (Properties.TryGetValue(s_accessibilityProperty, out ControlAccessibleObject? accObj))
if (Properties.TryGetValue(s_accessibilityProperty, out AccessibleObject? accObj)
&& accObj is ControlAccessibleObject controlAccObj)
{
accObj.Handle = IntPtr.Zero;
controlAccObj.Handle = IntPtr.Zero;
}

// Private accessibility object for control, used to wrap the object that
// OLEACC.DLL creates to represent the control's non-client (NC) region.
if (Properties.TryGetValue(s_ncAccessibilityProperty, out ControlAccessibleObject? nonClientAccessibleObject))
if (Properties.TryGetValue(s_ncAccessibilityProperty, out AccessibleObject? ncAccObj)
&& ncAccObj is ControlAccessibleObject nonClientAccessibleObject)
{
nonClientAccessibleObject.Handle = IntPtr.Zero;
}
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13 changes: 13 additions & 0 deletions src/test/unit/System.Windows.Forms/System/Windows/Forms/ControlTests.Methods.cs
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Expand Up @@ -412,6 +412,19 @@ public void Control_CreateAccessibilityInstance_Invoke_ReturnsExpected(bool crea
Assert.Equal(createHandle, control.IsHandleCreated);
}

[WinFormsFact]
public void Control_OnHandleDestroyed_CustomAccessibleObject_DoesNotThrow1()
{
using CustomCreateAccessibilityInstanceControl control = new()
{
CreateAccessibilityResult = new AccessibleObject()
};

AccessibleObject accessibleObject = control.AccessibilityObject;
Action action = () => control.InvokeOnHandleDestroyed(EventArgs.Empty);
action.Should().NotThrow();
}

[WinFormsFact]
public void Control_CreateControl_Invoke_Success()
{
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2 changes: 2 additions & 0 deletions src/test/unit/System.Windows.Forms/System/Windows/Forms/ControlTests.Properties.cs
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Expand Up @@ -100,6 +100,8 @@ private class CustomCreateAccessibilityInstanceControl : Control
public AccessibleObject CreateAccessibilityResult { get; set; }

protected override AccessibleObject CreateAccessibilityInstance() => CreateAccessibilityResult;

public void InvokeOnHandleDestroyed(EventArgs eventArgs) => OnHandleDestroyed(eventArgs);
}

[WinFormsTheory]
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