原文地址：ArcEngine 产生专题图作者：小生
ArcEngine提供多个着色对象用于产生专题图，可以使用标准着色方案，也可以自定义着色方案，ArcEngine提供8中标准着色方案。
一、SimpleRenderer专题图
是使用单一符号进行着色分类，不涉及对要素的数据进行处理。这种专题图同一个图层内的所有元素都是一种符号。
通过SimpleRenderer对象对Symbol进行设置后，赋予IGeoFeatureLayer接口的Renderer属性，对象实现了ITransparencyRenerer接口，通过该接口的属性，可以根据要素的某一个数值字段来设置要素显示的透明度。
该对象还实现了ISimpleRenderer接口，提供了两个重要的属性：Description和Label这两个属性用来设置图例。
/// <summary>
/// 简单渲染
/// </summary>
/// <param name="layerName">图层名字</param>
/// <param name="FillStyle">FillStyle</param>
/// <param name="pColor">FillColor</param>
/// <param name="OutLineColor">OutLineColor</param>
/// <param name="RenderLabel">样式名称注释</param>
/// <param name="Descripition">描述</param>
public void createSimpleFillSymbol(string layerName,esriSimpleFillStyle FillStyle,IColor pColor,IColor OutLineColor,string RenderLabel,string Descripition)
{
//简单填充符号
ISimpleFillSymbol simpleFillSymbol = new SimpleFillSymbolClass();
//可以用符号选择器进行
simpleFillSymbol.Style = FillStyle;
simpleFillSymbol.Color = pColor;
//创建边线符号
ISimpleLineSymbol simpleLineSymbol = new SimpleLineSymbolClass();
simpleLineSymbol.Style = esriSimpleLineStyle.esriSLSSolid;
simpleLineSymbol.Color = OutLineColor;
ISymbol symbol = simpleLineSymbol as ISymbol;
symbol.ROP2 = esriRasterOpCode.esriROPNotXOrPen;
simpleFillSymbol.Outline = simpleLineSymbol;
ISimpleRenderer simpleRender = new SimpleRendererClass();
simpleRender.Symbol = simpleFillSymbol as ISymbol;
simpleRender.Label = RenderLabel;
simpleRender.Description = Descripition;
IGeoFeatureLayer geoFeatureLayer;
geoFeatureLayer = getGeoLayer(layerName);
if (geoFeatureLayer != null)
{
geoFeatureLayer.Renderer = simpleRender as IFeatureRenderer;
}
}
二、ClassBreakRenderer专题图
为分级专题图，通过要素图层中要素的某个数值字段的值，根据用户要求，将这些值分为多个级别，每个级别用不同的Symbol显示。
该对象实现了IClassBreakRenderer接口，提供了实现分级显示的属性和方法，如Field属性用于设置分级着色的字段，BreakCount属性用于设置分级的数目。
/// <summary>
/// 分级渲染
/// </summary>
/// <param name="layerName">图层名</param>
/// <param name="classCount">分级数目</param>
/// <param name="ClassField">分级字段</param>
/// <param name="FillStyle">填充样式</param>
public void createClassBreakRender(string layerName, int classCount, string ClassField, esriSimpleFillStyle FillStyle)
{
//int classCount = 6;
ITableHistogram tableHistogram;//表格直方图
IBasicHistogram basicHistogram;//Provides access to members that control histogram objects created from different data sources.
ITable table;
IGeoFeatureLayer geoFeatureLayer;
geoFeatureLayer = getGeoLayer(layerName);
ILayer layer = geoFeatureLayer as ILayer;
table = layer as ITable;
tableHistogram = new BasicTableHistogramClass();
//按照 数值字段分级
tableHistogram.Table = table;
tableHistogram.Field = ClassField;
basicHistogram = tableHistogram as IBasicHistogram;
object values;
object frequencys;
//先统计每个值和各个值出现的次数
basicHistogram.GetHistogram(out values, out frequencys);
//创建平均分级对象
IClassifyGEN classifyGEN = new QuantileClass();
//用统计结果进行分级 ，级别数目为classCount
classifyGEN.Classify(values, frequencys, ref classCount);
//获得分级结果,是个 双精度类型数组
double[] classes;
classes = classifyGEN.ClassBreaks as double[];
//定义不同等级渲染的色带用色
IEnumColors enumColors = CreateAlgorithmicColorRamp(classes.Length).Colors;
IColor color;
IClassBreaksRenderer classBreaksRenderer = new ClassBreaksRendererClass();
classBreaksRenderer.Field = ClassField;
classBreaksRenderer.BreakCount = classCount;//分级数目
classBreaksRenderer.SortClassesAscending = true;//定义分类是否在TOC中显示Legend
ISimpleFillSymbol simpleFillSymbol;
for (int i = 0; i < classes.Length - 1; i++)
{
color = enumColors.Next();
simpleFillSymbol = new SimpleFillSymbolClass();
simpleFillSymbol.Color = color;
simpleFillSymbol.Style = FillStyle;
classBreaksRenderer.set_Symbol(i, simpleFillSymbol as ISymbol);
classBreaksRenderer.set_Break(i, classes[i]);
}
if (geoFeatureLayer != null)
{
geoFeatureLayer.Renderer = classBreaksRenderer as IFeatureRenderer;
}
}
三、UniqueValueRenderer专题图
是依据要素图层中的某个字段的不同值，给每个要素一个单独的颜色，以区分存在的每一个要素。
UniqueValueRenderer实现了IUniqueValueRenderer接口，提供了各种属性和方法，如AddValue方法用于将单个要素的某个字段值和与之相匹配的着色符号加入到UniqueValueRenderer对象。
/// <summary>
/// 单一值渲染（单字段）
/// </summary>
/// <param name="layerName">图层名</param>
/// <param name="RenderField">渲染字段</param>
/// <param name="FillStyle">填充样式</param>
/// <param name="valueCount">字段的唯一值个数</param>
public void createUniqueValueRander(string layerName, string RenderField, esriSimpleFillStyle FillStyle,int valueCount)
{
IGeoFeatureLayer geoFeatureLayer;
geoFeatureLayer = getGeoLayer(layerName);
IUniqueValueRenderer uniqueValueRenderer = new UniqueValueRendererClass();
//可以设置多个字段
uniqueValueRenderer.FieldCount = 1;//0-3个
uniqueValueRenderer.set_Field(0, RenderField);
//简单填充符号
ISimpleFillSymbol simpleFillSymbol = new SimpleFillSymbolClass();
simpleFillSymbol.Style = FillStyle;
IFeatureCursor featureCursor = geoFeatureLayer.FeatureClass.Search(null, false);
IFeature feature;
if (featureCursor != null)
{
IEnumColors enumColors = CreateAlgorithmicColorRamp(valueCount).Colors;
int fieldIndex = geoFeatureLayer.FeatureClass.Fields.FindField(RenderField);
for (int i = 0; i < valueCount; i++)
{
feature = featureCursor.NextFeature();
string nameValue = feature.get_Value(fieldIndex).ToString();
simpleFillSymbol = new SimpleFillSymbolClass();
simpleFillSymbol.Color = enumColors.Next();
uniqueValueRenderer.AddValue(nameValue, RenderField, simpleFillSymbol as ISymbol);
}
}
geoFeatureLayer.Renderer = uniqueValueRenderer as IFeatureRenderer;
}
/// <summary>
/// 单一值渲染(多字段）
/// </summary>
/// <param name="layerName">图层名</param>
/// <param name="RenderField">多字段名</param>
/// <param name="FillStyle">样式</param>
/// <param name="valueCount">每个字段中唯一值的个数</param>
public void createUniqueValueRander(string layerName, string[] RenderField, esriSimpleFillStyle FillStyle, int[] valueCount)
{
IGeoFeatureLayer geoFeatureLayer;
geoFeatureLayer = getGeoLayer(layerName);
IUniqueValueRenderer uniqueValueRenderer = new UniqueValueRendererClass();
//可以设置多个字段
uniqueValueRenderer.FieldCount = RenderField .Length;//0-3个
for (int i = 0; i < RenderField.Length; i++)
{
uniqueValueRenderer.set_Field(i, RenderField[i]);
}
//简单填充符号
ISimpleFillSymbol simpleFillSymbol = new SimpleFillSymbolClass();
simpleFillSymbol.Style = FillStyle;
IFeatureCursor featureCursor = geoFeatureLayer.FeatureClass.Search(null, false);
IFeature feature;
if (featureCursor != null)
{
for (int i = 0; i < RenderField.Length; i++)
{
IEnumColors enumColors = CreateAlgorithmicColorRamp(valueCount[i]).Colors;
int fieldIndex = geoFeatureLayer.FeatureClass.Fields.FindField(RenderField[i]);
for (int j = 0; j < valueCount[i]; j++)
{
feature = featureCursor.NextFeature();
string nameValue = feature.get_Value(fieldIndex).ToString();
simpleFillSymbol = new SimpleFillSymbolClass();
simpleFillSymbol.Color = enumColors.Next();
uniqueValueRenderer.AddValue(nameValue, RenderField[i], simpleFillSymbol as ISymbol);
}
}
}
geoFeatureLayer.Renderer = uniqueValueRenderer as IFeatureRenderer;
}
四、ProportionalSymbolRenderer专题图
使用梯度着色法制作的专题图。
ProportionalSymbolRenderer实现了IProportionalSymbolRenderer接口。
这种着色法需要用户知道最大和最小点各自代表的字段值、着色基于的字段和着色点使用的符号以及它在Legend要出现的级别数目。
/// <summary>
/// 梯度着色
/// </summary>
/// <param name="layerName">图层名字</param>
/// <param name="ProportionField">要参考的字段</param>
/// <param name="FillStyle">填充样式</param>
/// <param name="fillColor">填充Color</param>
/// <param name="characterMarkerSymbol">特征点符号</param>
/// <param name="units">参考单位</param>
/// <param name="pLegendSymbolCount">要分成的级数</param>
public void createProportionSymbolRender(string layerName, string ProportionField, esriSimpleFillStyle FillStyle, IColor fillColor, ICharacterMarkerSymbol characterMarkerSymbol, esriUnits units, int pLegendSymbolCount)
{
IGeoFeatureLayer geoFeatureLayer;
IFeatureLayer featureLayer;
IProportionalSymbolRenderer proportionalSymbolRenderer;
ITable table;
ICursor cursor;
IDataStatistics dataStatistics;//用一个字段生成统计数据
IStatisticsResults statisticsResult;//报告统计数据
//stdole.IFontDisp fontDisp;//定义字体
geoFeatureLayer = getGeoLayer(layerName);
featureLayer = geoFeatureLayer as IFeatureLayer;
table = geoFeatureLayer as ITable;
cursor = table.Search(null, true);
dataStatistics = new DataStatisticsClass();
dataStatistics.Cursor = cursor;
dataStatistics.Field = ProportionField;//确定分级字段
statisticsResult = dataStatistics.Statistics;
if (statisticsResult != null)
{
IFillSymbol fillSymbol = new SimpleFillSymbolClass();
fillSymbol.Color = fillColor;
//ICharacterMarkerSymbol characterMarkerSymbol = new CharacterMarkerSymbolClass();
//fontDisp = new stdole.StdFontClass() as stdole.IFontDisp;
//fontDisp.Name = "arial";
//fontDisp.Size = 20;
//characterMarkerSymbol.Font = fontDisp;
//characterMarkerSymbol.CharacterIndex = 90;
//characterMarkerSymbol.Color = getRGB(255, 0, 0);
//characterMarkerSymbol.Size = 8;
proportionalSymbolRenderer = new ProportionalSymbolRendererClass();
proportionalSymbolRenderer.ValueUnit = units;
proportionalSymbolRenderer.Field = ProportionField ;
proportionalSymbolRenderer.FlanneryCompensation = false;//分级是不是在TOC中显示legend
proportionalSymbolRenderer.MinDataValue = statisticsResult.Minimum;
proportionalSymbolRenderer.MaxDataValue = statisticsResult.Maximum;
proportionalSymbolRenderer.BackgroundSymbol = fillSymbol;
proportionalSymbolRenderer.MinSymbol = characterMarkerSymbol as ISymbol;
proportionalSymbolRenderer.LegendSymbolCount = pLegendSymbolCount;//要分成的级数
proportionalSymbolRenderer.CreateLegendSymbols();
geoFeatureLayer.Renderer = proportionalSymbolRenderer as IFeatureRenderer;
}
}
五、ChartRenderer专题图
使用一个饼图或柱图来表示一个要素的多个属性。有水平排列和累计排列两种。
ChartRenderer对象实现了IChartRenderer接口，其中ChartSymbol方法用于设置着色对象的着色符号，Label属性用于设置Legend的标签。
该方法用于比较一个要素中不同属性，在获得着色图层的单个或多个字段时用RendererField对象来操作。该类实现了IRendererField接口，可以通过AddField方法来添加字段。
该着色法是使用饼图来表现要素的多个属性之间的比率关系。该对象实现了IPicChartRenderer接口，使用PieChartSymbol符号来修饰要素。
/// <summary>
/// 条状图渲染
/// </summary>
/// <param name="layerName">图层名字</param>
/// <param name="RenderField">要柱状表示的字段</param>
/// <param name="fillsymbolColor">这些字段分别需要渲染的颜色</param>
/// <param name="BarWidth">每个柱子的宽度</param>
/// <param name="BgColor">背景色</param>
public void createBarChartSymbol(string layerName, string[] RenderField, IColor[] fillsymbolColor,double BarWidth,IColor BgColor)
{
IGeoFeatureLayer geoFeatureLayer;
IFeatureLayer featureLayer;
ITable table;
ICursor cursor;
IRowBuffer rowBuffer;
//获取渲染图层
geoFeatureLayer = getGeoLayer(layerName);
featureLayer = geoFeatureLayer as IFeatureLayer;
table = featureLayer as ITable;
geoFeatureLayer.ScaleSymbols = true;
IChartRenderer chartRenderer = new ChartRendererClass();
IRendererFields rendererFields = chartRenderer as IRendererFields;
for (int i = 0; i < RenderField.Length; i++)
{
rendererFields.AddField(RenderField[i], RenderField[i]);
}
//int[] fieldIndexs = new int[2];
//fieldIndexs[0] = table.FindField(field1);
//fieldIndexs[1] = table.FindField(field2);
//获取要素最大值，决定柱子的最大高度
double fieldValue = 0.0, maxValue = 0.0;
cursor = table.Search(null, true);
rowBuffer = cursor.NextRow();
while (rowBuffer != null)
{
for (int i = 0; i < RenderField.Length; i++)
{
int index = table.FindField(RenderField[i]);
fieldValue = double.Parse(rowBuffer.get_Value(index).ToString());
if (fieldValue > maxValue)
{
maxValue = fieldValue;
}
}
rowBuffer = cursor.NextRow();
}
//创建水平排列符号
IBarChartSymbol barChartSymbol = new BarChartSymbolClass();
barChartSymbol.Width = BarWidth;//柱子的边长
IMarkerSymbol markerSymbol = barChartSymbol as IMarkerSymbol;
markerSymbol.Size = 50;//这个是？
IChartSymbol chartSymbol = barChartSymbol as IChartSymbol;
chartSymbol.MaxValue = maxValue;
//添加渲染符号
ISymbolArray symbolArray = barChartSymbol as ISymbolArray;
IFillSymbol[] fillsymbol = new IFillSymbol[RenderField.Length];
for (int i = 0; i < RenderField.Length; i++)
{
//设置不同颜色的柱子
fillsymbol[i] = new SimpleFillSymbolClass();
fillsymbol[i].Color = fillsymbolColor[i];
symbolArray.AddSymbol(fillsymbol[i] as ISymbol);
//IFillSymbol fillSymbol = new SimpleFillSymbolClass();
//fillSymbol.Color = getRGB(255, 0, 0);//红色柱子
//symbolArray.AddSymbol(fillSymbol as ISymbol);
//fillSymbol = new SimpleFillSymbolClass();
//fillSymbol.Color = getRGB(0, 255, 0);//绿色柱子
//symbolArray.AddSymbol(fillSymbol as ISymbol);
}
//设置柱状图符号
chartRenderer.ChartSymbol = barChartSymbol as IChartSymbol;
//设置底图样式
IFillSymbol pFillSymbol = new SimpleFillSymbolClass();
pFillSymbol.Color = BgColor;
chartRenderer.BaseSymbol = pFillSymbol as ISymbol;
chartRenderer.UseOverposter = false;//假如那个位置放不下柱状图，是否用线段连接指示位置
//创建图例
chartRenderer.CreateLegend();
geoFeatureLayer.Renderer = chartRenderer as IFeatureRenderer;
}
/// <summary>
/// 创建累计柱状图表（stacked）
/// </summary>
/// <param name="layerName">Name</param>
/// <param name="RenderField">Fields</param>
/// <param name="fillsymbolColor">every Color</param>
/// <param name="BarWidth">width</param>
/// <param name="BgColor">BackGound Color</param>
public void createStackedChartSymbol(string layerName, string[] RenderField, IColor[] fillsymbolColor, double BarWidth, IColor BgColor)
{
IGeoFeatureLayer geoFeatureLayer;
IFeatureLayer featureLayer;
ITable table;
ICursor cursor;
IRowBuffer rowBuffer;
//获取渲染图层
geoFeatureLayer = getGeoLayer(layerName);
featureLayer = geoFeatureLayer as IFeatureLayer;
table = featureLayer as ITable;
geoFeatureLayer.ScaleSymbols = true;
IChartRenderer chartRenderer = new ChartRendererClass();
IRendererFields rendererFields = chartRenderer as IRendererFields;
for (int i = 0; i < RenderField.Length; i++)
{
rendererFields.AddField(RenderField[i], RenderField[i]);
}
//获取要素最大值
double fieldValue = 0.0, maxValue = 0.0;
cursor = table.Search(null, true);
rowBuffer = cursor.NextRow();
while (rowBuffer != null)
{
for (int i = 0; i < RenderField.Length ; i++)
{
int index = table.FindField(RenderField[i]);
fieldValue = double.Parse(rowBuffer.get_Value(index).ToString());
if (fieldValue > maxValue)
{
maxValue = fieldValue;
}
}
rowBuffer = cursor.NextRow();
}
//创建累积排列符号
IStackedChartSymbol stackedChartSymbol = new StackedChartSymbolClass();
stackedChartSymbol.Width = 10;//柱子宽度
IMarkerSymbol markerSymbol = stackedChartSymbol as IMarkerSymbol;
markerSymbol.Size = 50;//下面的大小
IChartSymbol chartSymbol = stackedChartSymbol as IChartSymbol;
chartSymbol.MaxValue = maxValue;
//添加渲染符号
ISymbolArray symbolArray = stackedChartSymbol as ISymbolArray;
IFillSymbol[] fillsymbol = new IFillSymbol[RenderField.Length];
for (int i = 0; i < RenderField.Length; i++)
{
//设置不同颜色的柱子
fillsymbol[i] = new SimpleFillSymbolClass();
fillsymbol[i].Color = fillsymbolColor[i];
symbolArray.AddSymbol(fillsymbol[i] as ISymbol);
}
//设置柱状图符号
chartRenderer.ChartSymbol = stackedChartSymbol as IChartSymbol;
IFillSymbol pFillSymbol = new SimpleFillSymbolClass();
pFillSymbol.Color =BgColor;
chartRenderer.BaseSymbol = pFillSymbol as ISymbol;
chartRenderer.UseOverposter = false;
//创建图例
chartRenderer.CreateLegend();
geoFeatureLayer.Renderer = chartRenderer as IFeatureRenderer;
}
/// <summary>
/// 创建饼图
/// </summary>
/// <param name="layerName">name</param>
/// <param name="RenderField">Fields</param>
/// <param name="fillsymbolColor">Each color</param>
/// <param name="BgColor">background Color</param>
public void createPieChartSymbol(string layerName, string[] RenderField, IColor[] fillsymbolColor, IColor BgColor)
{
IGeoFeatureLayer geoFeatureLayer;
IFeatureLayer featureLayer;
ITable table;
ICursor cursor;
IRowBuffer rowBuffer;
//获取渲染图层
geoFeatureLayer = getGeoLayer(layerName);
featureLayer = geoFeatureLayer as IFeatureLayer;
table = featureLayer as ITable;
geoFeatureLayer.ScaleSymbols = true;
IChartRenderer chartRenderer = new ChartRendererClass();
IPieChartRenderer pieChartRenderer = chartRenderer as IPieChartRenderer;
IRendererFields rendererFields = chartRenderer as IRendererFields;
for (int i = 0; i < RenderField.Length; i++)
{
rendererFields.AddField(RenderField[i], RenderField[i]);
}
//获取渲染要素的最大值
double fieldValue = 0.0, maxValue = 0.0;
cursor = table.Search(null, true);
rowBuffer = cursor.NextRow();
while (rowBuffer != null)
{
for (int i = 0; i < RenderField.Length ; i++)
{
int index = table.FindField(RenderField[i]);
fieldValue = double.Parse(rowBuffer.get_Value(index).ToString());
if (fieldValue > maxValue)
{
maxValue = fieldValue;
}
}
rowBuffer = cursor.NextRow();
}
//设置饼图符号
IPieChartSymbol pieChartSymbol = new PieChartSymbolClass();
pieChartSymbol.Clockwise = true;
pieChartSymbol.UseOutline = true;
IChartSymbol chartSymbol = pieChartSymbol as IChartSymbol;
chartSymbol.MaxValue = maxValue;
ILineSymbol lineSymbol = new SimpleLineSymbolClass();
lineSymbol.Color = getRGB(255, 0, 0);
lineSymbol.Width = 2;
pieChartSymbol.Outline = lineSymbol;
IMarkerSymbol markerSymbol = pieChartSymbol as IMarkerSymbol;
markerSymbol.Size = 30;
//添加渲染符号
ISymbolArray symbolArray = pieChartSymbol as ISymbolArray;
IFillSymbol[] fillsymbol =new IFillSymbol[RenderField.Length];
for (int i = 0; i < RenderField.Length; i++)
{
fillsymbol[i] = new SimpleFillSymbolClass();
fillsymbol[i].Color = fillsymbolColor[i];
symbolArray.AddSymbol(fillsymbol[i] as ISymbol);
}
//设置背景
chartRenderer.ChartSymbol = pieChartSymbol as IChartSymbol;
IFillSymbol pFillSymbol = new SimpleFillSymbolClass();
pFillSymbol.Color = BgColor;
chartRenderer.BaseSymbol = pFillSymbol as ISymbol;
chartRenderer.UseOverposter = false;
//创建图例
chartRenderer.CreateLegend();
geoFeatureLayer.Renderer = chartRenderer as IFeatureRenderer;
}
六、DotDensityRenderer专题图
DotDensityRenderer对象使用DotDensityFillSymbol符号对Polygon类型的要素进行着色。该专题图使用随机分布的点的密度来表现要素某个属性值得大小。也可以对图层的多个属性值着色，通过指定不同的点符号来区分。
DotDensityRenderer对象实现IDotDensityRenderer接口，定义了使用点密度着色方法和属性，如DotDensitySymbol用于确定着色点符号，CreateLegend方法用于产生图例。
/// <summary>
/// 点密度
/// </summary>
/// <param name="layerName">图层名字</param>
/// <param name="RenderField">渲染字段</param>
/// <param name="dotDensityFillSymbol">点密度符号</param>
/// <param name="simpleMarkerSymbol">点符号</param>
/// <param name="RenderDensity">点密度</param>
public void createDotDensityFillSymbol(string layerName, string RenderField, IDotDensityFillSymbol dotDensityFillSymbol, ISimpleMarkerSymbol simpleMarkerSymbol,double RenderDensity)
{
IGeoFeatureLayer geoFeatureLayer;
IDotDensityRenderer dotDensityRenderer;
//获取渲染图层
geoFeatureLayer = getGeoLayer(layerName);
dotDensityRenderer = new DotDensityRendererClass();
IRendererFields rendererFields = dotDensityRenderer as IRendererFields;
//设置渲染字段
rendererFields.AddField(RenderField, RenderField);
////设置填充颜色和背景色,直接由参数传入，具体定义参考下面的 例子
//dotDensityFillSymbol = new DotDensityFillSymbolClass();
//dotDensityFillSymbol.DotSize = 3;
//dotDensityFillSymbol.Color = getRGB(255, 0, 0);
//dotDensityFillSymbol.BackgroundColor = getRGB(0, 255, 0);
//设置渲染符号
ISymbolArray symbolArray = dotDensityFillSymbol as ISymbolArray;
//点符号样式，也可以参考下面的自己定义
//ISimpleMarkerSymbol simpleMarkerSymbol = new SimpleMarkerSymbolClass();
//simpleMarkerSymbol.Style = esriSimpleMarkerStyle.esriSMSCircle;
//simpleMarkerSymbol.Size = 2;
//simpleMarkerSymbol.Color = getRGB(0, 0, 255);
symbolArray.AddSymbol(simpleMarkerSymbol as ISymbol);
dotDensityRenderer.DotDensitySymbol = dotDensityFillSymbol;
//设置渲染密度
dotDensityRenderer.DotValue = RenderDensity;
//创建图例
dotDensityRenderer.CreateLegend();
geoFeatureLayer.Renderer = dotDensityRenderer as IFeatureRenderer;
}
此外还有两个补充方法（在调用这些方法的时候能用到）：
private IMap pMap;
public Renderer(IMap _pMap)
{
pMap = _pMap;
}
//获取颜色对象
private IRgbColor getRGB(int r, int g, int b)
{
IRgbColor pColor;
pColor = new RgbColorClass();
pColor.Red = r;
pColor.Green = g;
pColor.Blue = b;
return pColor;