dotnet/wpf · error · COMException

0x80040207

0x80040207

Error message

SR.TextStore_TS_E_INVALIDPOINT

What it means

TS_E_INVALIDPOINT (0x80040207) is thrown from GetPositionFromPoint when the point falls outside any character: layout was valid, but GetTextPositionFromPoint returned null because GXFPF_ROUND_NEAREST was clear and the point did not hit a character. It is the TSF HRESULT for 'the point is not over text'.

Solutions

1. Pass the GXFPF_ROUND_NEAREST flag so TSF rounds to the nearest character instead of failing.
2. Verify the client coordinate conversion (screen-to-client, DPI scaling) before hit-testing.
3. Only issue point queries for points inside the rendered text rectangle; clamp or reject outside points upstream.

Example fix

// before
var flags = 0; // GXFPF_ROUND_NEAREST clear -> point must hit a char exactly
// after
var flags = UnsafeNativeMethods.GetPositionFromPointFlags.GXFPF_ROUND_NEAREST; // snap to nearest char

// Only hit-test points inside the editor's text area; convert screen->client with DPI awareness first.
var pt = editor.PointFromScreen(screenPoint);
bool inside = editor.RenderSize.Width > pt.X && pt.X >= 0 && editor.RenderSize.Height > pt.Y && pt.Y >= 0;

catch (COMException e) when (e.ErrorCode == unchecked((int)0x80040207)) { /* point not over text: ignore or retry with GXFPF_ROUND_NEAREST */ }

When it happens

Trigger: ITextStoreACP::GetACPFromPoint called with a screen point that misses all text and without the GXFPF_ROUND_NEAREST flag (and GXFPF_NEAREST not producing a snap), so no text position can be returned.

Common situations: IME candidate/phrase-boundary clicks in empty areas beside text (margins, blank lines' trailing space); coordinate conversion mismatches (per-monitor DPI, wrong window origin) putting points off the text surface.

Related errors

• 0x80040206
• 0x80004001
• 0x80004002
• 0x80004005
• 0x80040200

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/55921db319c841bd. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Documents/TextStore.cs:965

            milPoint = compositionTarget.TransformFromDevice.Transform(milPoint);

            // Convert to local coordinates.
            GeneralTransform transform = compositionTarget.RootVisual.TransformToDescendant(RenderScope);
            // REVIEW: should we throw if the point could not be transformed?
            transform?.TryTransform(milPoint, out milPoint);

            // Validate layout information on TextView
            if (!view.Validate(milPoint))
            {
                throw new COMException(SR.TextStore_TS_E_NOLAYOUT, UnsafeNativeMethods.TS_E_NOLAYOUT);
            }

            // Do the hittest.
            position = view.GetTextPositionFromPoint(milPoint, (flags & UnsafeNativeMethods.GetPositionFromPointFlags.GXFPF_NEAREST) != 0 /* snapToText */);
            if (position == null)
            {
                // GXFPF_ROUND_NEAREST was clear and we didn't hit a char.
                throw new COMException(SR.TextStore_TS_E_INVALIDPOINT, UnsafeNativeMethods.TS_E_INVALIDPOINT);
            }

            positionCP = position.CharOffset;
            if ((flags & UnsafeNativeMethods.GetPositionFromPointFlags.GXFPF_ROUND_NEAREST) == 0)
            {
                // Check if the point is on the backward position of the TextPosition.
                Rect rectCur;
                Rect rectPrev;
                Point milPointTopLeft;
                Point milPointBottomRight;

                ITextPointer positionCur = position.CreatePointer(LogicalDirection.Backward);
                ITextPointer positionPrev = position.CreatePointer(LogicalDirection.Forward);
                positionPrev.MoveToNextInsertionPosition(LogicalDirection.Backward);

                rectCur = view.GetRectangleFromTextPosition(positionCur);
                rectPrev = view.GetRectangleFromTextPosition(positionPrev);

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