ArcEngine + C# 获取栅格数据像元值

此文问获得栅格数据的像元值（即高程），有可能部分见解不到位，望大神看到了不惜指教！

///

    ///  得到高程（通过像素值）
    /// 
    /// Raster路径
    private List GetElevation(string maskTifPath, List pointColList)//pointcollist是点集合，可以参照博文获得点集合
    {



        IRaster raster = GetRaster(maskTifPath);//参见博文获得raster数据
        //得到一段光栅带
        IRasterBandCollection rasterBandCollection = (IRasterBandCollection)raster;
        for (int icount = 0; icount < rasterBandCollection.Count; icount++)//测试数据count为1
        {
            IRasterBand rasterBand = rasterBandCollection.Item(icount);
            //像素
            IRawPixels rawPixels = (IRawPixels)rasterBand;
            IRasterProps rasterProps = (IRasterProps)rawPixels;
            //IGeoDataset geodataset = (IGeoDataset)raster;
            //IEnvelope2 envelop = new EnvelopeClass();
            //envelop = (IEnvelope2)geodataset.Extent;
            //IPoint point = envelop.UpperLeft;
            // 像元大致范围
            //double blockX = (double)rasterProps.MeanCellSize().X;//网格X间距
            //double blockY = (double)rasterProps.MeanCellSize().Y;//网格Y间距
            //double blockArea = blockX * blockY;//网格面积

            //int columns = rasterProps.Width;//dem列数
            //int rows = rasterProps.Height;//dem行数
            //   指定像素块大小
            IPnt blockSize = new DblPnt();
            //blockSize.X = columns;
            //blockSize.Y = rows;
            blockSize.X = 5;//赋值为多少比较合适？
            blockSize.Y = 5;
            //blockSize.X = blockX;
            //blockSize.Y = blockY;
            //指定像素块大小来创建像素快
            IPixelBlock3 pixelBlock = (IPixelBlock3)rawPixels.CreatePixelBlock(blockSize);
            IPnt blockOrigin = new DblPnt();
            IPoint point = new PointClass();
            List pixels = new List();
            for (int j = 0; j < pointColList.Count; j++)
            {
                point = pointColList[j];
                blockOrigin.X = point.X;
                blockOrigin.Y = point.Y;
                //   读取指定位置的像素块（blockOrigin为指定位置）
                rawPixels.Read(blockOrigin, (IPixelBlock)pixelBlock);
                //存储格网dem的二维数组
                System.Array pixelData = (System.Array)pixelBlock.get_PixelDataByRef(icount);
                // 获得每一个栅格的高程值
                for (int col = 0; col < pixelData.GetLength(0); col++)
                {
                    for (int row = 0; row < pixelData.GetLength(1); row++)
                    {
                        pixels.Add(Convert.ToInt32(pixelData.GetValue(col, row)));
                    }
                }
                return pixels;
            }

        }
    }