[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);

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;

}

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;

}