AO 创建饼图问题 跪请高人指点

<P>问什么不显示 请高人指点</P><P>  IChartRenderer mChartRenderer=new ChartRendererClass();<br>   IRendererFields mRendererFields=(IRendererFields)mChartRenderer;<br>   mRendererFields.AddField("NAME","特大");<br>    mRendererFields.AddField("NAME","重大");<br>   mRendererFields.AddField("NAME","一般");<br>   IBarChartSymbol mPieChartSymbol=new BarChartSymbolClass();<br>   mPieChartSymbol.Width=16;<br>   IMarkerSymbol mMarkerSymbol=(IMarkerSymbol)mPieChartSymbol;<br>   IChartSymbol mChartSymbol=(IChartSymbol)mPieChartSymbol;<br>            mChartSymbol.MaxValue=100;</P><P>   mMarkerSymbol.Size=36;<br>   mMarkerSymbol.XOffset=116.922566688791;<br>            mMarkerSymbol.YOffset=40.3866730555268;<br>           <br>   ISymbolArray mSymbolArray=(ISymbolArray)mPieChartSymbol;<br>   IFillSymbol mFillSymbol=new SimpleFillSymbolClass();<br>   mFillSymbol.Color=(ESRI.ArcGIS.Display.IColor)mMapMath.GetRGBColor(213,212,252);<br>   mSymbolArray.AddSymbol((ESRI.ArcGIS.Display.ISymbol)mFillSymbol);</P><P>   IFillSymbol sFillSymbol=new SimpleFillSymbolClass();<br>   sFillSymbol.Color=(ESRI.ArcGIS.Display.IColor)mMapMath.GetRGBColor(193,252,179);<br>   mSymbolArray.AddSymbol((ESRI.ArcGIS.Display.ISymbol)sFillSymbol);</P><P>            IFillSymbol pFillSymbol=new SimpleFillSymbolClass();<br>   pFillSymbol.Color=(ESRI.ArcGIS.Display.IColor)mMapMath.GetRGBColor(239,228,190);<br>            mSymbolArray.AddSymbol((ESRI.ArcGIS.Display.ISymbol)pFillSymbol);<br>      <br>   mChartRenderer.ChartSymbol =(ESRI.ArcGIS.Display.IChartSymbol)mPieChartSymbol;<br>   mChartRenderer.UseOverposter=false;<br>   mChartRenderer.BaseSymbol=(ESRI.ArcGIS.Display.ISymbol)pFillSymbol;<br>            mChartRenderer.CreateLegend();          <br>   <br>//   mChartRenderer.Label="火点统计图";<br>   IMap mMap=mMapControl.ActiveView.FocusMap;</P><P>   for(int i=0;i<mMap.LayerCount;i++)<br>   {   <br>    if(mMap.get_Layer(i).Name=="行政区界")<br>    {<br>                   mMap.get_Layer(i).Visible=false;<br>    }<br>    if(mMap.get_Layer(i).Name=="专题图层")<br>    {   <br>     mMap.get_Layer(i).Visible=true;<br>     IGeoFeatureLayer mGeoFeatureLayer=(IGeoFeatureLayer)mMap.get_Layer(i);<br>     mGeoFeatureLayer.DisplayAnnotation=false;<br>     mGeoFeatureLayer.Renderer=(ESRI.ArcGIS.Carto.IFeatureRenderer)mChartRenderer;<br>    }<br>   }<br>   mMapControl.ActiveView.Refresh();</P>