【发布时间】：2020-11-27 09:05:08
【问题描述】：
我需要导出存储在数据库（字节数组）中的具有不同文件类型（pdf、xlsx、.docx）的多个文件，并将它们保存为单个压缩文件。我应该如何处理多个文件？我假设我需要先将文件存储在列表中并使用 MemoryStream？我正在使用 ZipArchive 类将文件导出为 zip 文件。假设这种方法可行，我不确定如何将列表作为参数传递给 ZipArchive (DownloadMultipleFiles) 方法。
protected void lnkExport_Click(object sender, EventArgs e)
{
string applicationID = ((sender as LinkButton).CommandArgument);
var myList = GetFilesandConvertToList(applicationID);
DownloadMultipleFiles(myList); //How would I pass myList as an argument here? Obviously, this would not work.
}
调用存储过程来获取文件并将它们放在一个列表中：
public List<ZipList> GetFilesandConvertToList(string applicationID)
{
List<ZipList> fileList = new List<ZipList>();
SqlCommand cmd = new SqlCommand("dbo.spGetFilesByID", ConnC.con);
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.AddWithValue("@ApplicationID", applicationID); //This will return several files (different file types using the ID)
ConnC.con.Open();
using (SqlDataReader sdr = cmd.ExecuteReader())
{
if (sdr.HasRows)
{
while(sdr.Read())
{
ZipList zl = new ZipList();
sdr.Read();
zl.bytes = (byte[])sdr["FILE_CONTENT"];
zl.contentType = sdr["FILE_TYPE"].ToString();
zl.fileName = sdr["FILE_NAME"].ToString();
fileList.Add(zl);
}
}
}
return fileList;
}
使用 ZipArchive 将列表放入 MemoryStream 并导出为 zip 文件：
public void DownloadMultipleFiles(List<byte[]> byteArrayList)
{
using (MemoryStream ms = new MemoryStream())
{
using (ZipArchive archive = new ZipArchive(ms, ZipArchiveMode.Create, true))
{
foreach (byte[] file in byteArrayList)
{
ZipArchiveEntry entry = archive.CreateEntry(file.fileName + ".pdf", CompressionLevel.Fastest);
using (Stream zipStream = entry.Open())
{
zipStream.Write(file, 0, file.Length);
}
}
}
return File(ms.ToArray(), "application/zip", "Archive.zip");
}
}
public class ZipList
{
internal byte[] bytes;
internal string contentType;
internal string fileName;
}
更新：我已经用@Andy 稍微修改的答案更新了这个方法。这很好用：
protected void lnkExport_Click(object sender, EventArgs e)
{
string applicationID = ((sender as LinkButton).CommandArgument);
var myList = GetFilesandConvertToList(applicationID);
//Download Zipped File
byte[] fileBytes = GetZipFileForApplicationId(applicationID);
Response.Clear();
Response.Buffer = true;
Response.Charset = "";
Response.Cache.SetCacheability(HttpCacheability.NoCache);
Response.ClearContent();
Response.AppendHeader("Content-Disposition", "attachment; filename=Application.zip");
Response.AppendHeader("Content-Type", "application/zip");
Response.BinaryWrite(fileBytes);
HttpContext.Current.Response.Flush();
HttpContext.Current.Response.SuppressContent = true;
HttpContext.Current.ApplicationInstance.CompleteRequest();
}
使用@Andy 建议的方法将文件放入内存流并返回一个字节数组：
public byte[] GetZipFileForApplicationId(string applicationID)
{
byte[] fileBytes = null;
SqlCommand cmd = new SqlCommand("dbo.spGetFilesByID", ConnC.con);
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.AddWithValue("@ApplicationID", applicationID);
ConnC.con.Open();
using (SqlDataReader sdr = cmd.ExecuteReader())
{
if (sdr.HasRows)
{
using (MemoryStream ms = new MemoryStream())
{
using (ZipArchive archive = new ZipArchive(ms, ZipArchiveMode.Create, true))
{
while (sdr.Read())
{
byte[] bytes = (byte[])sdr["FILE_CONTENT"];
string contentType = sdr["FILE_TYPE"].ToString();
string fileName = sdr["FILE_NAME"].ToString();
ZipArchiveEntry entry = archive.CreateEntry(fileName);
using (Stream zipStream = entry.Open())
{
zipStream.Write(bytes, 0, bytes.Length);
}
}
}
ms.Position = 0;
fileBytes = ms.ToArray();
}
}
}
return fileBytes;
}
【问题讨论】：
-
@DaleK 当我尝试
DownloadMultipleFiles(List<ZipList>);我得到...is a type, which is not valid in the given context. -
我已将您的问题重新编辑以包含其原始内容，否则提供的答案将毫无意义。在这个网站上，您需要提出一个明确的问题，然后一旦人们发布了答案，就不要再从根本上改变它。如果您想向我们展示您最终使用的代码，请发布您自己的答案，因为这样未来的读者仍然清楚问题本身是什么以及可能的答案是什么。您也不应该将问题用作调试会话，如果您有其他问题，请再提出其他问题。
标签： c# asp.net memorystream