using System.Runtime.InteropServices;//引用,放在哪不用說了吧....[DllImport("dwmapi.dll")]public static extern int DwmExtendFrameIntoClientArea(IntPtr hWnd, ref MARGINS pMarinset);[StructLayout(LayoutKind.Sequential)]public struct MARGINS{  public int Right;  public int left;  public int Top;  public int Bottom;}private void Form1_Load(object sender, EventArgs e){  this.BackgroundImage = null;  MARGINS margins = new MARGINS();  margins.left = -1;  margins.Right = -1;  margins.Top = -1;  margins.Bottom = -1;  IntPtr hwnd = Handle;  int result = DwmExtendFrameIntoClientArea(hwnd, ref margins);  this.BackColor = Color.Black;  this.label1.Text = "。。。";  this.label1.BackColor = Color.Transparent;  this.label1.ForeColor = Color.White;}