winform 窗体移动API、窗体阴影API

//窗体移动API
[DllImport("user32.dll")]
public static extern bool ReleaseCapture();
[DllImport("user32.dll")]
public static extern bool SendMessage(IntPtr hwnd, int wMsg, int wParam, int IParam);
public const int WM_SYSCOMMAND = 0x0112;
public const int SC_MOVE = 0xF010;
public const int HTCAPTION = 0x0002;
[DllImport("user32")]
private static extern int SendMessage(IntPtr hwnd, int wMsg, int wParam, IntPtr lParam);
private const int WM_SETREDRAW = 0xB;



private void Form1_MouseDown(object sender, MouseEventArgs e)
{
    if (this.WindowState == FormWindowState.Normal)
    {
        ReleaseCapture();
        SendMessage(this.Handle, WM_SYSCOMMAND, SC_MOVE + HTCAPTION, 0);
    }
}

     //窗体阴影API
        const int CS_DropSHADOW = 0x20000;
        const int GCL_STYLE = (-26);
        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        public static extern int SetClassLong(IntPtr hwnd, int nIndex, int dwNewLong);
        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        public static extern int GetClassLong(IntPtr hwnd, int nIndex);


        public Form1()
        {
            InitializeComponent();
            SetClassLong(this.Handle, GCL_STYLE, GetClassLong(this.Handle, GCL_STYLE) | CS_DropSHADOW);
        }