填充样式的定义要用到ISimpleFillSymbol，或者要用到

具体实现如下：

//填充样式
ISimpleFillSymbol pFillsy;
pFillsy = new SimpleFillSymbolClass();
//pFillsy.Color = GetRgbColor(125, 60, 60);
pFillsy.Style = esriSimpleFillStyle.esriSFSCross;

GetRgbColor方法的实现如下：

/// <summary>
/// 取颜色
/// </summary>
/// <param name="red">红</param>
/// <param name="green">绿</param>
/// <param name="blue">蓝</param>
/// <returns>RgbColor</returns>
private RgbColor GetRgbColor(int red, int green, int blue)
{
//颜色
RgbColor rgbColor = new RgbColorClass();
rgbColor.Red = red;
rgbColor.Green = green;
rgbColor.Blue = blue;
return rgbColor;
}