用到某处要使用自定义颜色填充图像，貌似Graphics.FillRectangle方法只能用Brush来填充。但是常规Brush都是Brushes定义好的Brush，怎么办呢？
GOOGLE了下有两种方法：
一、用新SolidBrush填充
public void FillByColor(Rectangle rect,Color c,Graphics G){ G.FillRectangle(new SolidBrush(c), rect);}
参考文章：《如何：创建线性渐变》
二、用API实现指定颜色填充一个闭合区域(未测试)
用API实现指定颜色填充
using System.Runtime.InteropServices;[DllImport("gdi32.dll")]public static extern IntPtr SelectObject(IntPtr hdc, IntPtr hgdiobj);[DllImport("gdi32.dll")]public static extern IntPtr CreateSolidBrush(int crColor);[DllImport("gdi32.dll")]public static extern bool ExtFloodFill(IntPtr hdc, int nXStart, int nYStart, int crColor, uint fuFillType);[DllImport("gdi32.dll")]public static extern bool DeleteObject(IntPtr hObject);[DllImport("gdi32.dll")]public static extern int GetPixel(IntPtr hdc, int x, int y);public static uint FLOODFILLBORDER = 0;public static uint FLOODFILLSURFACE = 1;private void button1_Click(object sender, EventArgs e){ Graphics vGraphics = Graphics.FromHwnd(Handle); vGraphics.DrawRectangle(Pens.Blue, new Rectangle(0, 0, 300, 300)); vGraphics.DrawRectangle(Pens.Blue, new Rectangle(50, 70, 300, 300)); IntPtr vDC = vGraphics.GetHdc(); IntPtr vBrush = CreateSolidBrush(ColorTranslator.ToWin32(Color.Red)); IntPtr vPreviouseBrush = SelectObject(vDC, vBrush); ExtFloodFill(vDC, 10, 10, GetPixel(vDC, 10, 10), FLOODFILLSURFACE); SelectObject(vDC, vPreviouseBrush); DeleteObject(vBrush); vGraphics.ReleaseHdc(vDC);}
参考文章：http://www.csharpwin.com/csharpspace/9115r3566.shtml
（本文来源：http://www.cnblogs.com/allanswolf/archive/2010/04/22/1718217.html）
