C# WinForms prevent TrackBar scrolling but allow vertical scrolling-CodePudding

When you use the scroll wheel over a track bar, it changes the track bar value. I really don't like this behavior so I want to disable it. I found an easy solution here: https://stackoverflow.com/a/34928925

But the problem is this will prevent any vertical scrolling to happen whenever the mouse is over a track bar. Is there any way to allow vertical scrolling but prevent track bar scrolling?

CodePudding user response：

You can subclass the TrackBar then forward the mouse wheel messages to it's parent container.
Same idea as in this answer:
https://stackoverflow.com/a/57144200/2983568

// Subclass of TrackBar
public class TrackBarWithParentMouseWheel : TrackBar
{
    [DllImport("user32.dll", CharSet = CharSet.Auto)]
    private static extern IntPtr SendMessage(IntPtr hWnd, int msg, IntPtr wp, IntPtr lp);

    private const int WM_MOUSEWHEEL = 0x020A;

    protected override void WndProc(ref Message m)
    {
        if (m.Msg == WM_MOUSEWHEEL)
        {
            SendMessage(this.Parent.Handle, m.Msg, m.WParam, m.LParam);
            m.Result = IntPtr.Zero;
        }
        else base.WndProc(ref m);
    }
}


// Form.Designer.cs
this.trackBar1 = new TrackBarWithParentMouseWheel(); // in InitializeComponent()
private TrackBarWithParentMouseWheel trackBar1; // instead of private System.Windows.Forms.TrackBar trackBar1;