Winform自定义滚动条详细讲授

 1     public class Win32Api {
 2         [StructLayout(LayoutKind.Sequential)]
 3         public struct TagScrollinfo {
 4             public uint cbSize;
 5             public uint fMask;
 6             public int nMin;
 7             public int nMax;
 8             public uint nPage;
 9             public int nPos;
10             public int nTrackPos;
11         }
12 
13         public enum fnBar {
14             SB_HORZ = 0,
15             SB_VERT = 1,
16             SB_CTL = 2
17         }
18 
19         public enum fMask {
20             SIF_ALL,
21             SIF_DISABLENOSCROLL = 0X0010,
22             SIF_PAGE = 0X0002,
23             SIF_POS = 0X0004,
24             SIF_RANGE = 0X0001,
25             SIF_TRACKPOS = 0X0008
26         }
27 
28         public static int MakeLong(short lowPart, short highPart) {
29             return (int)(((ushort)lowPart) | (uint)(highPart << 16));
30         }
31 
32         public const int SB_THUMBTRACK = 5;
33         public const int WM_HSCROLL = 0x114;
34         public const int WM_VSCROLL = 0x115;
35 
36         [DllImport("user32.dll", EntryPoint = "GetScrollInfo")]
37         public static extern bool GetScrollInfo(IntPtr hwnd, int fnBar, ref Scrollinfo lpsi);
38 
39         [DllImport("user32.dll", EntryPoint = "SetScrollInfo")]
40         public static extern int SetScrollInfo(IntPtr hwnd, int fnBar, [In] ref Scrollinfo lpsi, bool fRedraw);
41 
42         [DllImport("User32.dll", CharSet = CharSet.Auto, EntryPoint = "SendMessage")]
43         public static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);
44 
45         //[DllImport("user32.dll", SetLastError = true)]
46         [DllImport("user32.dll", CallingConvention = CallingConvention.Winapi)]
47         public static extern bool PostMessage(IntPtr hWnd, uint Msg, long wParam, int lParam);
48 
49         public struct Scrollinfo {
50             public uint cbSize;
51             public uint fMask;
52             public int nMin;
53             public int nMax;
54             public uint nPage;
55             public int nPos;
56             public int nTrackPos;
57         }
58 
59         public enum ScrollInfoMask {
60             SIF_RANGE = 0x1,
61             SIF_PAGE = 0x2,
62             SIF_POS = 0x4,
63             SIF_DISABLENOSCROLL = 0x8,
64             SIF_TRACKPOS = 0x10,
65             SIF_ALL = SIF_RANGE + SIF_PAGE + SIF_POS + SIF_TRACKPOS
66         }
67 
68         public enum ScrollBarDirection {
69             SB_HORZ = 0,
70             SB_VERT = 1,
71             SB_CTL = 2,
72             SB_BOTH = 3
73         }
74     }

 1         /// <summary>
 2         /// 获取滚动条消息
 3         /// </summary>
 4         /// <returns></returns>
 5         private Win32Api.Scrollinfo GetScrollInfo()
 6         {
 7             Win32Api.Scrollinfo si = new Win32Api.Scrollinfo();
 8             si.cbSize = (uint)Marshal.SizeOf(si);
 9             si.fMask = (int)(Win32Api.ScrollInfoMask.SIF_DISABLENOSCROLL | Win32Api.ScrollInfoMask.SIF_ALL);
10             Win32Api.GetScrollInfo(this.TreeView.Handle, (int)Win32Api.ScrollBarDirection.SB_VERT, ref si);
11             return si;
12         }

 1         /// <summary>
 2         /// 设置控件的滚动条的位置
 3         /// </summary>
 4         /// <param name="scrollInfo"></param>
 5         /// <param name="pos"></param>
 6         private void SetControlScrollLocation(Win32Api.Scrollinfo scrollInfo, int pos) {
 7             Win32Api.Scrollinfo info = scrollInfo;
 8             info.nPos = pos;
 9             Win32Api.SetScrollInfo(this.TreeView.Handle, (int)Win32Api.ScrollBarDirection.SB_VERT, ref info, true);
10             IntPtr aa = new IntPtr(Win32Api.MakeLong((short)Win32Api.SB_THUMBTRACK, (short)(info.nPos)));
11             Win32Api.SendMessage(this.STreeView.Handle, Win32Api.WM_VSCROLL, aa, new IntPtr());
12         }