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今天项目有一新需求，需要从数据库中将文件打包，在客户端（BS架构）下载。由于系统将所有上传的文件都存储在数据库，这就牵涉到两点，首先要把数据库中的数据读出来，然后再利用ICSharpCode将文件打包。

 

由于是BS架构，因而不可能将数据库中的文件存储为某个临时文件，再进行打包，所以只好把文件以MemoryStream形式写入到Zip包中，同时需要注意的是，ZipEntry是不好重复的，如果碰到相同的文件名，是需要加以区分的，比如aaa.jpg，aaa(1).jpg，aaa(2).jpg。

 

在写入Zip包前，还需要用CRC来格式化buffer，就像是写到磁盘一样。

 

最后通过Response.OutputStream来实现客户端下载Zip文件。还有就是别忘记把Stream关闭。

 

 

下面这段代码就是实现了这样的需求。

 

 

            #region Initialize

            MemoryStream ziparchive = new MemoryStream();             ZipOutputStream MyZipStream = new ZipOutputStream(ziparchive);             // This is required inorder to close the zip archive and leave the stream intact             MyZipStream.IsStreamOwner = false;             // Set the compression level             MyZipStream.SetLevel(6);             bool? IsDefault = null;             bool? IsThumbnail = null;             if (ConvertClass.BooleanWrapper(rbtDownloadOptions.SelectedValue))             {                 IsDefault = true;             }             if (!ConvertClass.BooleanWrapper(rbtDownloadOptions.SelectedValue))             {                 IsThumbnail = true;             }             FileNameList.Clear();             #endregion             #region Get gift picture file into zip file             XmlDocument mXMLDocument = new XmlDocument();             mXMLDocument.LoadXml(GiftIDs);             XmlNodeList NodeList = mXMLDocument.SelectNodes("//items/item");             foreach (XmlNode idNode in NodeList)             {                 #region Get image stream                 // Get Image Data                 DataSet ds = DataSource;                 if (ds.Tables.Count == 0)                 {                     continue;                 }                 if (ds.Tables[0].Rows.Count == 0)                 {                     continue;                 }                 DataRow dr = ds.Tables[0].Rows[0];                 #endregion                 // This is how to get the data out of the stream                 byte[] buffer = (byte[])dr["GiftPicture"];                 MemoryStream stream = new MemoryStream(buffer);                 // Create the zip entry                 string entryName = string.Empty;                 if (ConvertClass.BooleanWrapper(rbtFileNameOptions.SelectedValue))                 {                     GiftEntity CurrentGift = new GiftEntity();                     CurrentGift.GiftID = ConvertClass.Int32Wrapper(idNode.Attributes["id"].Value);                     CurrentGift = DataSource;                     entryName = CurrentGift.GiftReference + GetFileExtensionName(dr["GiftPictureFileName"].ToString());                 }                 else                 {                     entryName = dr["GiftPictureFileName"].ToString();                 }                 ZipEntry entry = new ZipEntry(GetNonDuplicatedNameOfFile(entryName, 1));                 entry.DateTime = DateTime.Now;                 entry.Size = buffer.Length;                 // Use CRC to format the buffer                 Crc32 objCrc32 = new Crc32();                 objCrc32.Reset();                 objCrc32.Update(buffer);                 entry.Crc = objCrc32.Value;                 // Write the zip file                 MyZipStream.PutNextEntry(entry);                 MyZipStream.Write(buffer, 0, buffer.Length);                 stream.Close();             }             #endregion             #region Generate zip file             MyZipStream.Finish();             MyZipStream.Close();             // We have created the zip file and now it's time to serve it             Response.Clear();             Response.AddHeader("Content-Disposition", "attachment; filename=" + txtZIPFileName.Text + ".zip");             Response.ContentType = "application/x-zip-compressed";             byte[] ZipBuffer = new byte[ziparchive.Length - 1];             ZipBuffer = ziparchive.GetBuffer();             Response.OutputStream.Write(ZipBuffer, 0, Convert.ToInt32(ziparchive.Length));             Response.End();             MyZipStream.Close();             #endregion

 

 

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