dotnet/wpf

Scancode not passed to TSF

Open

#11635 opened on May 12, 2026

View on GitHub
 (0 comments) (1 reaction) (0 assignees)C# (6,683 stars) (1,126 forks)batch import
Good First Issue

Description

Description

The TextServiceManager does not pass scancode to Cicero/TSF

Reproduction Steps

https://github.com/dotnet/wpf/blob/7f005faa89e79b0b1fa1cb2c21283bab7916c092/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Input/TextServicesManager.cs#L232-L235

type anything using IME

Expected behavior

The scancode to be properly populated, e.g. from keyArgs.Scancode

Actual behavior

scancode seen in ITfKeyEventSink.On[Test]KeyDown is always 0

Regression?

no

Known Workarounds

reconstruct from virtual key

Impact

text services relying on scancodes do not work in WPF

Configuration

.NET 10/4.8, Windows 11, x64

Other information

No response

Contributor guide

Tech stack
csharp
Domain
desktop
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
C#WPF
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40
Research direction
Look at the TextServicesManager.cs file at line 232-235. The method needs to pass keyArgs.Scancode to the TSF sink. Investigate how other key arguments (like virtual key) are passed and replicate for scancode. Check the ITfKeyEventSink.OnTestKeyDown documentation to confirm the parameter. Implement the change and ensure it works with IME input.