将多个文件（具有不同文件类型）从数据库（字节数组）导出到单个压缩文件

Question

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，并将它们另存为单个压缩文件。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 class 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.
}

调用存储过程获取文件并将它们放入列表中：

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： 我已经用来自@Andy 的稍微修改过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和 return 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;
}

Answer 1

你似乎大部分时间都在那里，事实上我认为你需要使用 List<ZipList> 因为你的 byteArrayList 不包含 fileNameorLength` 的定义。

public void DownloadMultipleFiles(List<ZipList> zipList)
{
    using (MemoryStream ms = new MemoryStream())
    {
        using (ZipArchive archive = new ZipArchive(ms, ZipArchiveMode.Create, true))
        {
            foreach (var file in zipList)
            {
                ZipArchiveEntry entry = archive.CreateEntry(file.fileName + ".pdf", CompressionLevel.Fastest);
                using (Stream zipStream = entry.Open())
                {
                    zipStream.Write(file.bytes, 0, file.bytes.Length);
                }
            }
        }
        // Currently method returns void?
        // return File(ms.ToArray(), "application/zip", "Archive.zip");
        // Maybe you want
        File.WriteAllBytes("application/zip/Archive.zip", ms.ToArray());
    }
}

Answer 2

你可以用一块石头杀死几只鸟，而且不需要额外的模型就可以一次完成（这还没有经过测试，但你会明白要点）：

public byte[] GetZipFileForApplicationId(string applicationID)
{
    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 (var archive = new ZipArchive(ms, ZipArchiveMode.Create, true))
                {
                    while(sdr.Read())
                    {
                        var bytes = (byte[])sdr["FILE_CONTENT"];
                        var contentType = sdr["FILE_TYPE"].ToString();
                        var fileName = sdr["FILE_NAME"].ToString();
                        
                        var entry = archive.CreateEntry(fileName);
                        using (var zipStream = entry.Open())
                        {
                            zipStream.Write(bytes, 0, bytes.Length);
                        }
                    } 
                }
                ms.Position = 0;
                // This is kind of redundant. You should return the
                // MemoryStream object instead of duplicating it's data.
                // I'll let you play with that.
                return ms.ToArray();
            }
        }
    }
    return null;
}

将多个文件（具有不同文件类型）从数据库（字节数组）导出到单个压缩文件

Export multiple files (with different file types) from database (Byte Array) to single zipped file

c#

asp.net

memorystream