What causes "SR.ScreenCoordinatesOutsideBoundingRect" in dotnet/wpf?

Verify the point is inside the element's BoundingRectangle before calling RangeFromPoint.

dotnet/wpf · error · ArgumentException

SR.ScreenCoordinatesOutsideBoundingRect

Error message

SR.ScreenCoordinatesOutsideBoundingRect

What it means

TextPattern.RangeFromPoint throws ArgumentException when the given screen coordinate lies outside the element's current BoundingRectangle. The library checks the point against Left/Right/Top/Bottom before calling the provider, since a point outside the element cannot identify text within it.

Solutions

Verify the point is inside the element's BoundingRectangle before calling RangeFromPoint.
Convert client/window coordinates to absolute screen coordinates (PointToScreen) before passing them.
Re-read BoundingRectangle immediately before the call to account for window movement, and clamp or reject points outside it.

Example fix

// before
var range = textPattern.RangeFromPoint(clientPoint); // client-relative
// after
var screenPoint = element.Cached.BoundingRectangle.Contains(clientPoint) ? clientPoint : window.PointToScreen(clientPoint);
var rect = element.GetCurrentPropertyValue(AutomationElement.BoundingRectangleProperty) as Rect? ?? Rect.Empty;
if (!rect.Contains(screenPoint)) return null;
var range = textPattern.RangeFromPoint(screenPoint);

Defensive patterns

Strategy: validation

Validate before calling

var rect = (Rect)element.GetCurrentPropertyValue(AutomationElement.BoundingRectangleProperty);
bool inside = screenLocation.X >= rect.Left && screenLocation.X < rect.Right &&
              screenLocation.Y >= rect.Top && screenLocation.Y < rect.Bottom;
if (!inside) return null; // skip RangeFromPoint

Type guard

static bool IsWithinElement(AutomationElement el, Point p) =>
    el.GetCurrentPropertyValue(AutomationElement.BoundingRectangleProperty) is Rect r && r.Contains(p);

Try / catch

try { return textPattern.RangeFromPoint(screenLocation); }
catch (ArgumentException) { return null; // point outside element bounds }

Prevention

Always convert window/client coordinates to screen coordinates with PointToScreen
Capture Cursor.Position and use it immediately — the user may move the mouse
Re-read BoundingRectangle right before the call (windows move, DPI scales)
Account for multi-monitor negative coordinate spaces

When it happens

Trigger: Calling RangeFromPoint with screen coordinates from Cursor.Position or a mouse hook where the cursor has moved outside the element (e.g. off-window, over a title bar, or over another control) between capture and the call.

Common situations: Screen coordinates vs client coordinates confusion (passing client-relative points); cursor moved by user after point capture; DPI scaling or multi-monitor coordinates not translated to screen space; automation running while the window is dragged or minimized.

Understand the failure class

Background: "value must be between 0 and 1" / "out of range" / "must not be negative" errors: fixing range-validation failures across open-source libraries — this error's family across 42 libraries.

Related errors

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/1b06ee4aed61fab7. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/UIAutomation/UIAutomationClient/System/Windows/Automation/TextPattern.cs:220

            return TextPatternRange.Wrap(hTextRange, this);
        }
        /// <summary>
        /// Finds the range nearest to a screen coordinate.
        /// If the coordinate is within the bounding rectangle of a character then the
        /// range will contain that character.  Otherwise, it will be a degenerate
        /// range near the point, chosen in an implementation-dependent manner.
        /// An InvalidOperation exception is thrown if the point is outside of the
        /// client area of the text container.
        /// </summary>
        /// <param name="screenLocation">The location in screen coordinates.</param>
        /// <returns>A degenerate range nearest the specified location.</returns>
        public TextPatternRange RangeFromPoint(Point screenLocation)
        {
            //If we are not within the client area throw an exception
            Rect rect = (Rect)_element.GetCurrentPropertyValue(AutomationElement.BoundingRectangleProperty);
            if (screenLocation.X < rect.Left || screenLocation.X >= rect.Right || screenLocation.Y < rect.Top || screenLocation.Y >= rect.Bottom)
            {
                throw new ArgumentException(SR.ScreenCoordinatesOutsideBoundingRect);
            }

            SafeTextRangeHandle hTextRange = UiaCoreApi.TextPattern_RangeFromPoint(_hPattern, screenLocation);
            return TextPatternRange.Wrap(hTextRange, this);
        }

        #endregion Public Methods
        
        //------------------------------------------------------
        //
        //  Public Properties
        //
        //------------------------------------------------------
 
        #region Public Properties

        /// <summary>
        /// A text range that encloses the main text of the document.  Some auxillary text such as

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