dotnet/wpf · error · InvalidOperationException

SR.OperationCannotBePerformed

Error message

SR.OperationCannotBePerformed

What it means

WindowsSysHeader's Invoke pattern implementation clicks the header item by simulating WM_LBUTTONDOWN/UP at the item's on-screen center. GetInvokationPoint computes that point; when it fails (e.g. the item cannot be located on screen), Invoke throws InvalidOperationException with SR.OperationCannotBePerformed.

Solutions

1. Ensure the header's parent window is visible and restored (not minimized) before Invoke.
2. Scroll the header/item into view before invoking; the proxy already attempts parent ScrollIntoView but it can fail for hidden windows.
3. Run automation in an interactive desktop session instead of a headless service context.

Example fix

// before
invokePattern.Invoke();
// after
if (window.WindowPattern.Current.WindowVisualState != WindowVisualState.Normal)
    windowPattern.ShowWindow(WindowVisualState.Normal);
invokePattern.Invoke();

if (!headerElement.Current.IsOffscreen && windowVisualState != WindowVisualState.Minimized) invokePattern.Invoke();

static bool IsInvokableOnScreen(AutomationElement e) => !e.Current.IsOffscreen && e.Current.IsEnabled;

try { invokePattern.Invoke(); }
catch (InvalidOperationException) { /* item not on screen / window hidden; restore and retry */ }

When it happens

Trigger: Calling IInvokeProvider.Invoke on a header control item whose screen coordinates cannot be obtained (item scrolled out of view, parent unavailable, or the window is minimized/hidden).

Common situations: Clicking column headers of a listview that is minimized or on an invisible virtual desktop; header items scrolled horizontally out of the visible area; automation running in a hidden session (e.g. CI service without interactive desktop).

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

• Element is not enabled.
• Element is not enabled.
• Operation cannot be performed.
• Operation cannot be performed.
• ' ' is not a valid value for this control.

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/e50fb1ee550f4ca9. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/UIAutomation/UIAutomationClientSideProviders/MS/Internal/AutomationProxies/WindowsSysHeader.cs:475

            #region Invoke Pattern

            // Same as a click on one of the header element
            void IInvokeProvider.Invoke ()
            {
                // Make sure that the control is enabled
                if (!SafeNativeMethods.IsWindowEnabled(_hwnd))
                {
                    throw new ElementNotEnabledException();
                }

                WindowsSysHeader parent = _parent as WindowsSysHeader;
                parent?.ScrollIntoView(this);

                NativeMethods.Win32Point pt;

                if (!GetInvokationPoint (out pt))
                {
                    throw new InvalidOperationException(SR.OperationCannotBePerformed);
                }

                IntPtr center = NativeMethods.Util.MAKELPARAM (pt.x, pt.y);

                // click
                Misc.ProxySendMessage(_hwnd, NativeMethods.WM_LBUTTONDOWN, new IntPtr(NativeMethods.MK_LBUTTON), center);
                Misc.ProxySendMessage(_hwnd, NativeMethods.WM_LBUTTONUP, IntPtr.Zero, center);
            }

            #endregion Invoke Pattern
            #region ExpandCollapse Pattern

            void IExpandCollapseProvider.Expand ()
            {
                if (!IsExpanded())
                {
                    ClickSplitButton();
                }

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