使用IUniqueValueRenderer在同一层中根据字段渲染出不同颜色收藏

public static void UniqueValueRenderer(ILayer layer)

  {

   IFeatureLayer pFLayer = layer  as IFeatureLayer;

   IGeoFeatureLayer geoLayer = layer as IGeoFeatureLayer;

   IFeatureClass fcls = pFLayer.FeatureClass;

   IQueryFilter pQueryFilter = new  QueryFilterClass();

   IFeatureCursor fCursor = fcls.Search(pQueryFilter,false);

   IRandomColorRamp rx = new RandomColorRampClass();

   rx.MinSaturation = 15;

   rx.MaxSaturation = 30;

   rx.MinValue = 85;

   rx.MaxValue = 100;

   rx.StartHue = 0;

   rx.EndHue = 360;

   rx.Size =100;

   bool ok;;

   rx.CreateRamp(out ok);

   IEnumColors RColors = rx.Colors;

   RColors.Reset();

   IUniqueValueRenderer pRender = new UniqueValueRendererClass();

   pRender.FieldCount=1;

   pRender.set_Field(0,"乡名");

   IFeature pFeat = fCursor.NextFeature();

   int index = pFeat.Fields.FindField("乡名");

   while(pFeat!=null)

   {

    ISimpleFillSymbol symd = new SimpleFillSymbolClass();

    symd.Style=esriSimpleFillStyle.esriSFSSolid;

    symd.Outline.Width=1;

    symd.Color = RColors.Next();

    string valuestr = pFeat.get_Value(index).ToString();

    pRender.AddValue(valuestr,valuestr,symd as ISymbol);

    pFeat = fCursor.NextFeature();

   }

   geoLayer.Renderer = pRender as IFeatureRenderer;

  }