WinCE平台下C＃引用API（GDI）里面关注内存条泄漏

由于C＃精简框架集绘图函数不支持圆角矩形，所以引用了相关的API。

[DllImport("\\windows\\coredll.dll", EntryPoint = "RoundRect")] private static extern int CeRoundRect(IntPtr hdc, int X1, int Y1, int X2, int Y2, int X3, int Y3);

这是有内存泄漏的源码：

public static int RoundRect(Graphics e, Pen pen, SolidBrush brush, int X1, int Y1, int X2, int Y2, int X3, int Y3) {         IntPtr hpen; IntPtr hbrush; if(pen!=null) { hpen = CreatePen((DashStyle.Solid == pen.DashStyle) ? 0 : 1, (int)pen.Width, SetRGB(pen.Color.R, pen.Color.G, pen.Color.B)); //创建GDI画笔  } else { hpen = GetStockObject(8);      //空画笔 }          if (brush!= null) { hbrush = CreateSolidBrush(SetRGB(brush.Color.R, brush.Color.G, brush.Color.B)); //brush.Color.ToArgb()); } else { hbrush = GetStockObject(5); } //pen.Dispose(); //brush.Dispose(); IntPtr hdc = e.GetHdc(); //---------------------   SelectObject(hdc, hbrush); SelectObject(hdc, hpen); int intRet=RoundRect(hdc, X1, Y1, X2,Y2, X3, Y3); DeleteObject(hbrush); DeleteObject(hpen); //--------------------- e.ReleaseHdc(hdc); return intRet; }

这是没有问题的源码：

public static int RoundRect(Graphics e, Pen pen, SolidBrush brush, int X1, int Y1, int X2, int Y2, int X3, int Y3) {         IntPtr hpen,old_pen; IntPtr hbrush, old_brush; if(pen!=null) { hpen = CreatePen((DashStyle.Solid == pen.DashStyle) ? 0 : 1, (int)pen.Width, SetRGB(pen.Color.R, pen.Color.G, pen.Color.B));      //创建GDI画笔  } else { hpen = GetStockObject(8);      //空画笔 }          if (brush!= null) { hbrush = CreateSolidBrush(SetRGB(brush.Color.R, brush.Color.G, brush.Color.B)); //brush.Color.ToArgb()); } else { hbrush = GetStockObject(5); } //pen.Dispose(); //brush.Dispose(); IntPtr hdc = e.GetHdc(); //---------------------   old_brush=SelectObject(hdc, hbrush); old_pen=SelectObject(hdc, hpen); int intRet=RoundRect(hdc, X1, Y1, X2,Y2, X3, Y3); SelectObject(hdc, old_brush); SelectObject(hdc, old_pen); DeleteObject(hbrush); DeleteObject(hpen); //--------------------- e.ReleaseHdc(hdc); return intRet; }

看出代码的区别来了没有？泄漏的原因其实很简单，就是没有重新选入旧的画笔画刷。同样的程序（当然PC端的API库是GDI32）在上位机Window XP平台上没有什么问题（测试大约3天以上），而在WinCE平台确非常明显，大约1～3个小时（视圆角矩形绘图的多寡而定），该程序就会内存耗尽而死。

来源链接：http://blog.csdn.net/yefanqiu/archive/2006/12/05/1430411.aspx

（68476636-8007）