dotnet/wpf · error · InvalidOperationException

SR.OperationCannotBePerformed

Error message

SR.OperationCannotBePerformed

What it means

WindowsListViewGroup.GetPreviousSibling computes the previous item's position as groupInfo.IndexOf(current) - 1 and throws InvalidOperationException (SR.OperationCannotBePerformed) when prevLocation <= -2, i.e. the current item was not found at index >= 0 in the group's item list. This indicates the proxy's cached logical tree is out of sync with the native ListView control.

Solutions

1. Re-find the element (fresh FindFirst) instead of reusing a cached UIA element after list mutations.
2. Pause traversal or retry after list modification events settle.
3. Catch InvalidOperationException and treat it as 'tree changed; restart navigation'.

Example fix

// before
var prev = item.AutomationElement.GetPreviousSibling(); // may throw after re-sort
// after
try { prev = item.AutomationElement.GetPreviousSibling(); }
catch (InvalidOperationException) { item = list.FindFirst(...); prev = item.AutomationElement.GetPreviousSibling(); }

try { prev = walker.GetPreviousSibling(el); }
catch (InvalidOperationException) { el = ReacquireElement(); prev = walker.GetPreviousSibling(el); }

When it happens

Trigger: Walking the UIA TreeWalker (GetPreviousSibling) over ListView items after the native control reordered, removed, or regrouped items without the proxy receiving the corresponding WinEvents; IndexOf(current) then returns -1 so prevLocation becomes -2.

Common situations: Automation scripts traversing siblings while the ListView is being re-sorted, items deleted, or the control switched between view modes (e.g. to List mode, which has no groups); stale UIA element references.

Understand the failure class

Background: "Invalid state transition" errors: "status must be X, actually Y", "already rejected/charging/uninstalled", "cannot ... while running" — what they mean when a library rejects your call — this error's family across 31 libraries.

Related errors

• E_OUTOFMEMORY
• Element no longer available.
• Element no longer available.
• ElementNotAvailableException
• ElementNotAvailableException

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/ee53334fa977bc09. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/UIAutomation/UIAutomationClientSideProviders/MS/Internal/AutomationProxies/WindowsListViewGroup.cs:200

            {
                int [] items = groupInfo._items;
                int current = child._item;

                // The subset link has an index that is one past the list items
                // If we are on that then the previous is the last item in the items array.
                if (_isComctrlV6OnOsVerV6orHigher && current == groupInfo._count)
                {
                    int index = items [groupInfo._count - 1];

                    return CreateListViewItem (index);
                }

                // find the index of the current lvitem
                int prevLocation = groupInfo.IndexOf (current) - 1;

                if (prevLocation <= -2)
                {
                    throw new InvalidOperationException(SR.OperationCannotBePerformed);
                }

                if (prevLocation >= 0)
                {
                    return CreateListViewItem (items [prevLocation]);
                }
            }

            return null;
        }

        // Returns the first child element in the raw hierarchy.
        internal override ProxySimple GetFirstChild ()
        {
            // return first item in this group
            GroupManager.GroupInfo groupInfo = GetGroupInfo (_hwnd, ID);

            if (groupInfo)

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