How to Detect Stylus Pen Sides (Pen Tip vs. Eraser) in WPF (C#)

Question

Hello,

I’m developing a WPF application in C# that interacts with a stylus pen on a Windows device. I need to detect which side of the stylus is being used—whether it’s the pen tip or the eraser side.

Could someone guide me on how to achieve this programmatically in WPF? Specifically:

Are there specific APIs or libraries in WPF or Windows Ink that can detect the stylus side (pen or eraser)?

If possible, I’d appreciate any code examples, documentation references, or guidance on implementing this feature in WPF.

Thank you in advance for your help!

Answer 1

Hi, @Manjunath PM. Welcome to Microsoft Q&A. 

You could try using StylusDevice.Inverted to check whether the stylus tip or the eraser is currently being used.

For example: Bind OnStylusMove to the StylusDown event and edit the following code

private void OnStylusMove(object sender, StylusEventArgs e)
{
    StylusDevice myStylusDevice = e.StylusDevice;

    if (myStylusDevice != null)
    {
        if (myStylusDevice.Inverted)
        {
            textbox1.Text = "stylus moves with eraser down";
        }
        else
        {
            textbox1.Text = "stylus moves with pen down";
        }
    }
}

Related Documents: StylusDevice.Inverted Property (System.Windows.Input) | Microsoft Learn

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