惟一值渲染

該着色方法一句着色圖層中要素類的某個數值字段的屬性值，按這個屬性值爲每種不一樣值得要素單獨分配一種顯示符號樣式。關鍵在於獲取該字段全部要素的惟一值（即將全部在該字段中屬性值相同的要素歸爲一種），利用UniqueValueRenderer的AddValue方法便可進行渲染

須要添加的類庫

1 using System.Collections;
2 using System.Windows.Forms;
3 using ESRI.ArcGIS.Display;
4 using ESRI.ArcGIS.Carto;
5 using ESRI.ArcGIS.esriSystem;
6 using ESRI.ArcGIS.Geodatabase;

具體代碼（本例爲單值渲染）

 1 private ISymbol GetSymbol(IColor pColor)
 2         {
 3             ISymbol pSymbol;
 4             ISimpleFillSymbol pSymbolFillSymbol = new SimpleFillSymbolClass();
 5             pSymbolFillSymbol.Color = pColor;
 6             pSymbolFillSymbol.Outline.Width = 0.4;
 7             pSymbol = pSymbolFillSymbol as ISymbol;
 8             return pSymbol;
 9         }
10  private void uniqueValueRendererToolStripMenuItem_Click(object sender, EventArgs e)
11         {
12             IMap pMap = this.axMapControl1.ActiveView.FocusMap;
13             if (pMap.LayerCount== 0)
14             {
15                 MessageBox.Show("地圖爲空，請加載地圖！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Warning);
16                 return;
17             }
18             IGeoFeatureLayer pGeoLayer = this.axMapControl1.get_Layer(0) as IGeoFeatureLayer ;
19             ITable pTable = pGeoLayer.FeatureClass as ITable;
20             ICursor pCursor;
21             IQueryFilter pQueryFilter = new QueryFilter();
22             pQueryFilter.AddField("PERIMETER");
23             pCursor = pTable.Search(pQueryFilter, true);//獲取字段
24             IEnumerator pEnumreator;
25 
26             //獲取字段中各要素屬性惟一值
27             IDataStatistics pDataStatistics = new DataStatisticsClass();
28             pDataStatistics.Field = "PERIMETER";//獲取統計字段
29             pDataStatistics.Cursor = pCursor;
30             pEnumreator = pDataStatistics.UniqueValues;
31             int fieldcount = pDataStatistics.UniqueValueCount;//惟一值個數，以此肯定顏色帶範圍
32 
33             IUniqueValueRenderer pUniqueValueR = new UniqueValueRendererClass();
34             pUniqueValueR.FieldCount = 1;//單值渲染
35             pUniqueValueR.set_Field(0, "PERIMETER");//渲染字段
36             IEnumColors pEnumColor = GetColorRamp(fieldcount).Colors;
37             pEnumColor.Reset();
38 
39             while (pEnumreator.MoveNext())
40             {
41                 string value = pEnumreator.Current.ToString();
42                 if (value != null)
43                 {
44                     IColor pColor = pEnumColor.Next();
45                     ISymbol pSymbol = GetSymbol(pColor);
46                     pUniqueValueR.AddValue(value, "PERIMETER", pSymbol);
47                     //pUniqueValueR.set_Symbol(value, pSymbol);
48                     
49                 }
50  
51             }
52             pGeoLayer.Renderer = pUniqueValueR as IFeatureRenderer;
53             this.axMapControl1.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewGeography, null, null);
54             this.axTOCControl1.Update();
55             
56         }
57         private IRandomColorRamp GetColorRamp(int size)
58         {
59             IRandomColorRamp pRandomColorRamp = new RandomColorRampClass();
60             pRandomColorRamp.StartHue = 10;
61             pRandomColorRamp.EndHue = 300;
62             pRandomColorRamp.MaxSaturation =100;
63             pRandomColorRamp.MinSaturation = 0;
64             pRandomColorRamp.MaxValue = 100;
65             pRandomColorRamp.MinValue = 0;
66             pRandomColorRamp.Size = size;
67             bool ok = true;
68             pRandomColorRamp.CreateRamp(out ok);
69             return pRandomColorRamp;
70         }

其中datastatistic和uniqueValueRenderer的field必需要明確，且爲相同值