学步园

using System.Runtime.InteropServices; 
//并为控件 添加 MouseDown 事件

// C#鼠标拖动任意控件

// 利用Windows的API函数：SendMessage 和 ReleaseCapture 
const uint WM_SYSCOMMAND = 0x0112;
const uint SC_MOVE = 0xF010;
const uint HTCAPTION = 0x0002;

[DllImport("user32.dll", EntryPoint = "SendMessageA")]
private static extern int SendMessage(IntPtr hwnd, uint wMsg, uint wParam, uint lParam);
[DllImport("user32.dll")]
private static extern int ReleaseCapture();

void ControlMouseDown(object sender, MouseEventArgs e)
{
    ReleaseCapture();
    SendMessage((sender as Control).Handle, WM_SYSCOMMAND, SC_MOVE + HTCAPTION, 0);
}