使用UniqueValue方法渲染地图

代码：

IGeoFeatureLayer m_pGeoFeatureL; IUniqueValueRenderer pUniqueValueR; IFillSymbol pFillSymbol; IColor pNextUniqueColor; IEnumColors pEnumRamp; ITable pTable; int lfieldNumber; IRow pNextRow; IRowBuffer pNextRowBuffer; ICursor pCursor; IQueryFilter pQueryFilter; string codeValue; IRandomColorRamp pColorRamp; string strNameField = "地区"; IActiveView pActiveView; IMap pMap; pActiveView = this.axMapControl1.ActiveView; pMap = this.axMapControl1.Map; pMap.ReferenceScale = 0; m_pGeoFeatureL = (IGeoFeatureLayer)pMap.get_Layer(4); pUniqueValueR = new UniqueValueRendererClass(); pTable = (ITable)m_pGeoFeatureL; //ᡒߎSTATE_NAME೼ᄫ↉Ёⱘ㓪ো lfieldNumber = pTable.FindField(strNameField); if (lfieldNumber == -1) { MessageBox.Show("找不到字段： " + strNameField); return; } pUniqueValueR.FieldCount = 1; pUniqueValueR.set_Field(0, strNameField); pColorRamp = new RandomColorRampClass(); pColorRamp.StartHue = 0; pColorRamp.MinValue = 99; pColorRamp.MinSaturation = 15; pColorRamp.EndHue = 360; pColorRamp.MaxValue = 100; pColorRamp.MaxSaturation = 30; pColorRamp.Size = 6; bool ok = true; pColorRamp.CreateRamp(out ok); pEnumRamp = pColorRamp.Colors; pNextUniqueColor = null; pQueryFilter = new QueryFilterClass(); pQueryFilter.AddField(strNameField); pCursor = pTable.Search(pQueryFilter, true); pNextRow = pCursor.NextRow(); while (pNextRow != null) { pNextRowBuffer = pNextRow; codeValue = (string)pNextRowBuffer.get_Value(lfieldNumber);//提高速度 pNextUniqueColor = pEnumRamp.Next(); if (pNextUniqueColor == null) { pEnumRamp.Reset(); pNextUniqueColor = pEnumRamp.Next(); } pFillSymbol = new SimpleFillSymbolClass(); pFillSymbol.Color = pNextUniqueColor; pUniqueValueR.AddValue(codeValue, strNameField, (ISymbol)pFillSymbol); pNextRow = pCursor.NextRow(); } m_pGeoFeatureL.Renderer = (IFeatureRenderer)pUniqueValueR; pActiveView.PartialRefresh(esriViewDrawPhase.esriViewGeography, null, null);

这种做法有时会出现一个问题：无法保证MapControl和TOC控件的样式一致，尤其是出现颜色不一致的情况，例如，MapControl里中国区域为红色，但TOC里可能表示为另外一个颜色，无论如何刷新都无法是TOC正确显示。尚不知道原因。