ArcGIS Engine 渲染----饼图

这几天一直看AE,几天看下来没什么头绪,日子过得恍恍忽忽.今天终于写了一个程序练练手,根据帮助的VB程序改编的,在众多的接口之间跳来跳去,晕头转向.现把代码贴出来,给处在迷茫中的朋友一点小启示,也以此自勉!

画饼图,C#实现:

private RgbColor GetRgbColor(int red,int green,int blue)
{
RgbColor rgbColor = new RgbColorClass();
rgbColor.Red = red;
rgbColor.Green = green;
rgbColor.Blue = blue;

return rgbColor;
}

private void btnPieChart_Click(object sender,EventArgs e)
{
IMap pMap = new MapClass();
IFeatureLayer pFLayer = (IFeatureLayer)axMapControl1.get_Layer(0);
IGeoFeatureLayer pGeoFeaLayer = (IGeoFeatureLayer)pFLayer;

IChartRenderer pChartRenderer = new ChartRendererClass();

// Set up the field to draw charts

IRendererFields pRenderFields = (IRendererFields)pChartRenderer;
pRenderFields.AddField("Pop_cntry",null);
IPieChartRenderer pPieChartRender = (IPieChartRenderer)pChartRenderer;

//Calculate the max value of the data field to scale the chart

//ICursor pCursor = new CursorClass();

IQueryFilter pQueryFilter = new QueryFilterClass();
//IRowBuffer pRow = new RowBufferClass();
ITable pTable = (ITable)pGeoFeaLayer;
pQueryFilter.AddField("Pop_cntry");
ICursor pCursor = pTable.Search(pQueryFilter,true);

int fieldIndex;
double MaxValue;
bool firstValue;
double fieldValue;

fieldIndex = pTable.FindField("Pop_cntry");
firstValue = true;
MaxValue = 0;

IRowBuffer pRow = pCursor.NextRow();
while (pRow != null)
{
fieldValue =(double) pRow.get_Value(fieldIndex);
if (firstValue)
{
MaxValue = fieldValue;
firstValue = false;
}

if (fieldValue > MaxValue)
{
MaxValue = fieldValue;
}
pRow = pCursor.NextRow();
}

IPieChartSymbol pPiechartSymbol = new Pie ChartSymbolClass();
IFillSymbol pFillSymbol = new SimpleFillSymbolClass();

IChartSymbol pChartSymbol = (IChartSymbol)pPiechartSymbol;
pPiechartSymbol.Clockwise = true;
pPiechartSymbol.USEOutline = true;

ILineSymbol pOutLine = new SimpleLineSymbolClass();
pOutLine.Color = GetRgbColor(255,255);
pOutLine.Width = 1;
pPiechartSymbol.Outline = pOutLine;

IMarkerSymbol pMarkerSymbol = (IMarkerSymbol)pPiechartSymbol;

//finally

pChartSymbol.MaxValue = MaxValue;

pMarkerSymbol.Size = 16;

ISymbolArray pSymbolArray = (ISymbolArray)pPiechartSymbol;
pFillSymbol.Color = GetRgbColor(213,212,252);

pFillSymbol.Outline = pOutLine;
pSymbolArray.AddSymbol((ISymbol)pFillSymbol);

//set up the background

pFillSymbol.Color = GetRgbColor(239,228,190);
pChartRenderer.BaseSymbol = (ISymbol)pFillSymbol;

pChartRenderer.USEOverposter = false;

pPieChartRender.MinSize = 6;

pPieChartRender.MinValue = 453588;
pPieChartRender.FlanneryCompensation = false;
pPieChartRender.ProportionalBySum = true;

pChartRenderer.ChartSymbol = (IChartSymbol)pPiechartSymbol;
pChartRenderer.CreateLegend();
pGeoFeaLayer.Renderer =(IFeatureRenderer) pChartRenderer;

this.axLicenseControl1.Refresh();

}

来自：http://www.3snews.net/html/47/6447-9536.html

（编辑：李大同）

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