MouseGesture not getting called correctly when being added to InputGestureCollection

[SetTrend]

Problem description:

Having created a custom command like this:

public static RoutedUICommand ZoomIn { get; } = new RoutedUICommand("Zoom in", "ZoomIn", typeof(CustomCommands), new InputGestureCollection() { new KeyGesture(Key.OemPlus, ModifierKeys.Control), new MouseWheelGesture(WheelDirection.Down, ModifierKeys.Control) });

And having written a MouseWheelGesture like described here: https://stackoverflow.com/questions/2271342/mousebinding-the-mousewheel-to-zoom-in-wpf-and-mvvm#answer-7527482

The MouseWheelGesture.Matches() method is not getting called when the mouse wheel is rotated while the CTRL key is getting pressed.

Actual behavior:

The MouseWheelGesture.Matches() method is getting called for the CTRL key is being pressed, but not for the mouse wheel being rotated.

Expected behavior:

The MouseWheelGesture.Matches() method should be getting called when the mouse wheel being rotated with a MouseWheelEventArgs event argument.

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• .NET Core Version: (e.g. 3.0 Preview1, or daily build number, use dotnet --info)

  
  .NET SDK (gemäß "global.json"):
  Version:   5.0.400
  Commit:    d61950f9bf

Laufzeitumgebung: OS Name: Windows OS Version: 10.0.19043 OS Platform: Windows RID: win10-x64 Base Path: C:\Program Files\dotnet\sdk\5.0.400\

Host (useful for support): Version: 5.0.9 Commit: 208e377a53

.NET SDKs installed: 3.1.412 [C:\Program Files\dotnet\sdk] 5.0.303 [C:\Program Files\dotnet\sdk] 5.0.400 [C:\Program Files\dotnet\sdk]

.NET runtimes installed: Microsoft.AspNetCore.All 2.1.29 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.App 2.1.29 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 3.1.18 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 5.0.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.NETCore.App 2.1.29 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 3.1.18 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 5.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.WindowsDesktop.App 3.1.18 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App] Microsoft.WindowsDesktop.App 5.0.9 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

To install additional .NET runtimes or SDKs: https://aka.ms/dotnet-download

* Windows version: (`winver`)

21H1 Build 19043.1165

[singhashish-wpf]

@SetTrend Please attach your sample app where you are able to reproduce the issue.

[SetTrend]

@singhashish-wpf:

Please find the MCVE here: SetTrend/mousegestureissue

I added steps to reproduce to the example repository's ReadMe.md file.

[SetTrend]

Did anyone have the time to investigate on this issue?

[SetTrend]

Did anyone have the time to investigate on this issue?

[h3xds1nz]

@SetTrend

1) You're calling base.Matches first, but your override initializes with MouseAction.None, on which the base (MouseGesture) call will always return false.

Therefore we have two solutions: 1) Initialize with MouseAction.WheelClick instead of MouseAction.None, then your code works out of the box. 2) Stop using the base check and check yourself for Modifiers flags (using Keyboard.Modifiers as source of truth, which is what MouseGesture does) + that the event is MouseWheelEventArgs.

[SetTrend]

Excellent answer! Thanks a lot for enlightening me!

[h3xds1nz]

Welcome, only took 3 years to figure this one out, right 😄