将Mxd文件压缩并上传到Geodatabase！

把Mxd文件压缩上传测试代码！

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO.Compression;
using System.IO;
using ESRI.ArcGIS.DataSourcesGDB;
using ESRI.ArcGIS.esriSystem;
using ESRI.ArcGIS.Geodatabase;
using ESRI.ArcGIS.Geometry;
namespace CompressMxd
{
    class CompressMxdFile
    {
        public static IWorkspace OpenWorkspace(string mdbPath)
        {
            IWorkspaceFactory pwspfact=new AccessWorkspaceFactoryClass();
            IWorkspace pwsp = pwspfact.OpenFromFile(mdbPath, 0);
            return pwsp;
        }
        public static bool ReadAndCompressMxdFile(string fileName, IWorkspace pwsp)
        {
            byte[] buffer = null;
            try
            {
                using (System.IO.FileStream sourceStream = new System.IO.FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.Read))
                {
                    buffer = new byte[sourceStream.Length];
                    int checkCounter = sourceStream.Read(buffer, 0, buffer.Length);
                    byte[] compressBytes = Compress(buffer);

                    MemoryBlobStream blob = new MemoryBlobStream();
                    ((IMemoryBlobStreamVariant)blob).ImportFromVariant(compressBytes as object);//将一个Byte[]对象作为参数传入

                    IFeatureWorkspace pFwsp = pwsp as IFeatureWorkspace;
                    ITable ptable = pFwsp.OpenTable("MxdCollection");
                    IRow row = ptable.CreateRow();
                    var idx = row.Fields.FindField("MxdFile");
                      IField field = ptable.Fields.get_Field(idx);
                      if (field.CheckValue(blob))
                      {
                          row.set_Value(idx, blob as object);
                      }
                      row.Store();
                }
            }
            catch (System.Exception ex)
            {
                return false;
            }
           
            return true;
        }
        public static bool DeCompressMxdFile(string fileName,IWorkspace pwsp)
        {
            
            IFeatureWorkspace pFwsp = pwsp as IFeatureWorkspace;
            ITable ptable = pFwsp.OpenTable("MxdCollection");
            IRow row = ptable.GetRow(4);
            var idx = row.Fields.FindField("MxdFile");
            object objtest =  row.get_Value(idx);
           
            IMemoryBlobStreamVariant pVar = objtest as IMemoryBlobStreamVariant;
            object pobj = new object();
            pVar.ExportToVariant(out pobj); //转入Object对象
            byte[] desbytes = Decompress((byte[])pobj);
            using (System.IO.FileStream destinationStream = new System.IO.FileStream(fileName, FileMode.Create))
            {
                destinationStream.Write(desbytes,0,desbytes.Length);
            }
            return true;
        }
        private static byte[] Compress(byte[] bytes)
        {
            using (MemoryStream ms = new MemoryStream())
            {
                GZipStream Compress = new GZipStream(ms, CompressionMode.Compress);

                Compress.Write(bytes, 0, bytes.Length);

                Compress.Close();

                return ms.ToArray();

            }
        }

        private static byte[] Decompress(Byte[] bytes)
        {
            using (MemoryStream tempMs = new MemoryStream())
            {
                using (MemoryStream ms = new MemoryStream(bytes))
                {
                    GZipStream Decompress = new GZipStream(ms, CompressionMode.Decompress);

                    Decompress.CopyTo(tempMs);

                    Decompress.Close();

                    return tempMs.ToArray();
                }
            }
        }
    }
}

　　这里的这个思路和代码完全可以将任何文件上传到Geodatabase中！当然文件大小是受限制的。这和Access有关和机器的位数有关，在Oracle中是否可以放开一些文件大小方面的限制？

　　对文件进行管理，通过Hash算法进行文件的版本控制！这个想法确实不错，不过具体要做成什么样子呢，我也不知道！

　　微软提供了Compress（Gzipstream类）和Security命名空间分别实现了LZ77和哈弗曼编码结合的压缩算法，实现了加密的算法，可以直接调用。

　　说实话不太喜欢拿来主义，用是很方便，但是真的不是自己做出来的，感觉理解方面还是有很多困难。不知道其内部机制到底是怎样的！！！

　　不知道如果Mxd文档调用的要素类是服务器中的，我的Mxd文档下载到任意客户端是否都能够显示图形要素！