fo-dicom/Desktop/DICOM Compare/ListViewEx.cs

// Copyright (c) 2012-2020 fo-dicom contributors.
// Licensed under the Microsoft Public License (MS-PL).

using System.Windows.Forms;

namespace Dicom.Compare
{
   internal class ListViewEx : ListView
   {
      private const int WM_VSCROLL = 0x0115;

      private const int WM_MOUSEWHEEL = 0x020A;

      public event ScrollEventHandler Scroll;

      protected virtual void OnScroll(ScrollEventArgs e)
      {
         Scroll?.Invoke(this, e);
      }

      protected override void WndProc(ref Message m)
      {
         base.WndProc(ref m);

         if (m.Msg == WM_VSCROLL) OnScroll(new ScrollEventArgs((ScrollEventType)(m.WParam.ToInt32() & 0xffff), 0));

         else if (m.Msg == WM_MOUSEWHEEL) OnScroll(new ScrollEventArgs(ScrollEventType.EndScroll, 0));
      }
   }
}