獲取柵格欄位的唯一值：

        /// <summary>
        /// 獲取柵格欄位的唯一值
        /// </summary>
        /// <param name="pLayer">柵格圖層</param>
        /// <param name="field">欄位</param>
        /// <returns>唯一值</returns>
        public static string[] GetRasterUniqueValue(ILayer pLayer, string
 
 field)
        {
            IRasterLayer pRlyr = pLayer as IRasterLayer;
            if (pRlyr == null) return null;
            //判斷是否存在屬性表
            if (!IsRasterLayerHaveTable(pRlyr.Raster)) return null;
            ITable pRTable = (ITable)pRlyr;
            //獲得柵格遊標 
            ICursor pCursor = pRTable.Search(null
 
, false);
            //IDataStatistics物件例項生成
            IDataStatistics pData = new DataStatisticsClass();
            pData.Field = field; //欄位
            pData.Cursor = pCursor;
            //列舉唯一值
            IEnumerator pEnumVar = pData.UniqueValues;
            //記錄總數
            int recordCount = pData.UniqueValueCount;
            //字元陣列
 

            string[] strValue = new string[recordCount];
            pEnumVar.Reset(); //將遊標重置到第一個成員前面
            int i = 0;
            while (pEnumVar.MoveNext()) //將遊標的內部位置向前移動
            {
                if (pEnumVar.Current != null) strValue[i++] = pEnumVar.Current.ToString(); //獲取當前的項（只讀屬性）
            }
            return strValue;
        }

判斷柵格圖層是否存在屬性表：

        /// <summary>
        /// 判斷柵格圖層是否擁有屬性表
        /// </summary>
        /// <param name="pRaster">柵格</param>
        /// <returns>是否擁有屬性表</returns>
        public static bool IsRasterLayerHaveTable(IRaster pRaster)
        {
            IRasterProps pProp = pRaster as IRasterProps;
            if (pProp == null)
            {
                return false;
            }
            if (pProp.PixelType == rstPixelType.PT_FLOAT || pProp.PixelType == rstPixelType.PT_DOUBLE) //判斷柵格像元值是否是整型
            {
                return false;
            }
            IRasterBandCollection pRasterbandCollection = (IRasterBandCollection)pRaster;
            IRasterBand rasterBand = pRasterbandCollection.Item(0);
            ITable rTable = rasterBand.AttributeTable;
            return rTable != null;
        }