Winforms - Adjust width of vertical scrollbar on CheckedListBox

Question

I have a CheckListBox on my form but I want to make the scrollbar wider as users are using touch screens not a mouse.

How can I change the scroll bar width?

EDIT: I am talking about the width of the vertical scrollbar

Answer 1

To change the physical size of the scrollbar, see this.

This came from the following page: Horizontal Scrollbar in ListBox. I modified it for Winforms and it worked for me:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace CheckedListBoxScrollBarsWidth
{
   public partial class Form1 : Form
   {
      const int LB_GETHORIZONTALEXTENT = 0x0193;
      const int LB_SETHORIZONTALEXTENT = 0x0194;

      const long WS_HSCROLL = 0x00100000L;

      const int SWP_FRAMECHANGED = 0x0020;
      const int SWP_NOMOVE = 0x0002;
      const int SWP_NOSIZE = 0x0001;
      const int SWP_NOZORDER = 0x0004;

      const int GWL_STYLE = (-16);    

      public Form1()
      {
         InitializeComponent();
         checkedListBox1.HorizontalScrollbar = true;
         AddStyle(checkedListBox1.Handle, (uint)WS_HSCROLL);
         SendMessage(checkedListBox1.Handle, LB_SETHORIZONTALEXTENT, 1000, 0);
      }

      [DllImport("user32.dll")]
      static extern int SendMessage(IntPtr hwnd, int msg, int wParam, int lParam);

      [DllImport("user32.dll")]
      static extern uint GetWindowLong(IntPtr hwnd, int index);

      [DllImport("user32.dll")]
      static extern void SetWindowLong(IntPtr hwnd, int index, uint value);

      [DllImport("user32.dll")]
      static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int X,
            int Y, int cx, int cy, uint uFlags);


      private void AddStyle(IntPtr handle, uint addStyle)
      {
         // Get current window style
         uint windowStyle = GetWindowLong(handle, GWL_STYLE);

         // Modify style
         SetWindowLong(handle, GWL_STYLE, windowStyle | addStyle);

         // Let the window know of the changes
         SetWindowPos(handle, IntPtr.Zero, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOZORDER | SWP_NOSIZE | SWP_FRAMECHANGED);
      }
   }
}