public void SetBits() { //绘制绘图层背景 Bitmap bitmap = new Bitmap(Main.Width + 10, Main.Height + 10); Rectangle _BacklightLTRB = new Rectangle(20, 20, 20, 20);//窗体光泽重绘边界 Graphics g = Graphics.FromImage(bitmap); g.SmoothingMode = SmoothingMode.HighQuality; //高质量 g.PixelOffsetMode = PixelOffsetMode.HighQuality; //高像素偏移质量 ImageDrawRect.DrawRect(g, Properties.Resources.main_light_bkg_top123, ClientRectangle, Rectangle.FromLTRB(_BacklightLTRB.X, _BacklightLTRB.Y, _BacklightLTRB.Width, _BacklightLTRB.Height), 1, 1); if (!Bitmap.IsCanonicalPixelFormat(bitmap.PixelFormat) || !Bitmap.IsAlphaPixelFormat(bitmap.PixelFormat)) throw new ApplicationException("图片必须是32位带Alhpa通道的图片。"); IntPtr oldBits = IntPtr.Zero; IntPtr screenDC = Win32.GetDC(IntPtr.Zero); IntPtr hBitmap = IntPtr.Zero; IntPtr memDc = Win32.CreateCompatibleDC(screenDC); try { Win32.Point topLoc = new Win32.Point(Left, Top); Win32.Size bitMapSize = new Win32.Size(Width, Height); Win32.BLENDFUNCTION blendFunc = new Win32.BLENDFUNCTION(); Win32.Point srcLoc = new Win32.Point(0, 0); hBitmap = bitmap.GetHbitmap(Color.FromArgb(0)); oldBits = Win32.SelectObject(memDc, hBitmap); blendFunc.BlendOp = Win32.AC_SRC_OVER; blendFunc.SourceConstantAlpha = Byte.Parse("255"); blendFunc.AlphaFormat = Win32.AC_SRC_ALPHA; blendFunc.BlendFlags = 0; Win32.UpdateLayeredWindow(Handle, screenDC, ref topLoc, ref bitMapSize, memDc, ref srcLoc, 0, ref blendFunc, Win32.ULW_ALPHA); } finally { if (hBitmap != IntPtr.Zero) { Win32.SelectObject(memDc, oldBits); Win32.DeleteObject(hBitmap); } Win32.ReleaseDC(IntPtr.Zero, screenDC); Win32.DeleteDC(memDc); } }

网上看到大部分无边框窗体阴影 都是只有右边和底部有阴影的，本源码不仅实现了四边阴影，而且包括圆角，淡入淡出等特效都有。调用非常方便，只要引用类库，需要特效的窗口继承SkinMain就可以了。

winform 窗体四边阴影winform 窗体四边阴影winform 窗体四边阴影winform 窗体四边阴影 mark。markmarkmarkmark

代码封装成类库，在自己的项目中引用类库，需要加阴影的窗体把继承: Form修改成: SkinMain即可