分级渲染--百度地图路段红黄绿功能

/* 参数一：要渲染的图层

    参数二：按照哪个属性渲染

    参数三：分级的分解点

    参数四：各级的颜色*/

public void linkClassRender(IFeatureLayer layer, string fieldName, List<int> spds, List<IColor> colors)        

{            

　　// 获取当前图层，并把它设置成IGeoFeatureLayer的实例            

　　IFeatureLayer pFeatLayer = (IFeatureLayer)layer;

      IGeoFeatureLayer pGeoFeatLayer = (IGeoFeatureLayer)layer;            

　　IFeatureClass pFeatClass = pFeatLayer.FeatureClass;　　

　　IClassBreaksRenderer pClassBreaksRenderer = new ClassBreaksRendererClass();            

　　pClassBreaksRenderer.Field = fieldName;            

　　pClassBreaksRenderer.MinimumBreak = spds[0];            

　　pClassBreaksRenderer.BreakCount = spds.Count - 1;             

      for (int breakIndex = 0; breakIndex < spds.Count-1; breakIndex++)            

　　{

                pClassBreaksRenderer.set_Label(breakIndex, spds[breakIndex] + "-" + spds[breakIndex + 1]);

                ISimpleLineSymbol pLineSymbol = new SimpleLineSymbolClass();

                pLineSymbol.Color = colors[breakIndex];

                pLineSymbol.Width = 2;                

　　　　　  pClassBreaksRenderer.set_Symbol(breakIndex, (ISymbol)pLineSymbol);

                pClassBreaksRenderer.set_Break(breakIndex, spds[breakIndex + 1]);            

　　}            

　　// 将等级图渲染对象与渲染图层挂钩            

　　pGeoFeatLayer.Renderer = (IFeatureRenderer)pClassBreaksRenderer;            

　　axMapControl1.Refresh();        

}

/* 使用示例*/

protected void Render()        

{            

　　 FeatureLayer pFLayer = GetLayerbyName("road") as FeatureLayer;

       List<int> spdCls = new List<int>();            

 　　spdCls.Add(0); spdCls.Add(3); spdCls.Add(5); spdCls.Add(7); spdCls.Add(9);            

　　// 分成4段 0-3 3-5 5-7 7-9                        

　　List<IColor> colors = new List<IColor>();            

　　colors.Add(GetIColorByRGB(0,255,0));            

　　colors.Add(GetIColorByRGB(255, 255, 0));            

　　colors.Add(GetIColorByRGB(255, 0, 0));            

　　colors.Add(GetIColorByRGB(125,125,125));            

　　linkClassRender(pFLayer, "SPEEDCLASS", spdCls, colors);        

}

public IColor GetIColorByRGB(int r,int g,int b)
{　　

　　IRgbColor color1 = new RgbColorClass() ;　　

　　color1.Red = r;
      color1.Green = g;　　

      color1.Blue = b;
      return color1 as IColor;
}