.net 为电子邮件附件压缩MemoryStream
我正在尝试压缩XML树并将其用作电子邮件附件。发送带有附件的电子邮件成功,但创建的zip文件始终损坏–它不是有效的zip文件,但包含二进制数据 此问题将按如下方式重新创建,具体请参见.net 为电子邮件附件压缩MemoryStream,.net,zip,attachment,deflatestream,.net,Zip,Attachment,Deflatestream,我正在尝试压缩XML树并将其用作电子邮件附件。发送带有附件的电子邮件成功,但创建的zip文件始终损坏–它不是有效的zip文件,但包含二进制数据 此问题将按如下方式重新创建,具体请参见BuildAttachment(): 把问题放在上下文中:它是windows服务应用程序的一部分,所以我不想在磁盘上创建文件,电子邮件还包含xslt转换的xml树的替代视图,所以我不想使用完全不同的解决方案 有任何关于zip文件损坏原因的建议吗?您不是在创建有效的zip文件,而是在创建压缩流并将其写入扩展名为*.zi
BuildAttachment()
:
把问题放在上下文中:它是windows服务应用程序的一部分,所以我不想在磁盘上创建文件,电子邮件还包含xslt转换的xml树的替代视图,所以我不想使用完全不同的解决方案
有任何关于zip文件损坏原因的建议吗?您不是在创建有效的zip文件,而是在创建压缩流并将其写入扩展名为
*.zip的文件。您应该使用.NET zip库,而不是DeflateStream
您可以使用以下内容:
DotNetZip是一个易于使用、快速、免费的类库和工具集
操作zip文件或文件夹。压缩和解压缩很容易:使用
用VB、C#-任何.NET语言编写的.NET应用程序-
可以轻松创建、读取、提取或更新zip文件。单声道或多声道
.NET
如果您有限制并且无法使用外部库,您可以尝试使用GZipStream
,并添加扩展名为*.gz
的附件,这将由常用压缩工具支持
作为将来参考的有用信息,.NET 4.5最终将通过该类引入对zip存档的本机支持。为了将来参考,可接受答案中建议的生成.gz存档的备用GZipStream
方法通过如下更改上述代码来实现
static Attachment BuildAttachment(XElement report)
{
var inStream = new MemoryStream();
report.Save(inStream);
inStream.Position = 0;
var outStream = new MemoryStream();
using (var compress = new GZipStream(outStream, CompressionMode.Compress))
{
inStream.CopyTo(compress);
compress.Close();
}
var ms = new MemoryStream(outStream.ToArray());
Attachment attachment = new Attachment(ms, "report.xml.gz", "application/gzip");
return attachment;
}
需要使用using
块和ToArray()
调用 我知道这是一个老问题,但当我在寻找同样的问题时,它出现了
下面是我使用[基于ACRAI5075的答案]添加压缩(zip)附件的解决方案:
byte[] report = GetSomeReportAsByteArray();
string fileName = "file.txt";
using (MemoryStream memoryStream = new MemoryStream())
{
using (ZipArchive zipArchive = new ZipArchive(memoryStream, ZipArchiveMode.Update))
{
ZipArchiveEntry zipArchiveEntry = zipArchive.CreateEntry(fileName);
using (StreamWriter streamWriter = new StreamWriter(zipArchiveEntry.Open()))
{
streamWriter.Write(Encoding.Default.GetString(report));
}
}
MemoryStream attachmentStream = new MemoryStream(memoryStream.ToArray());
Attachment attachment = new Attachment(attachmentStream, fileName + ".zip", MediaTypeNames.Application.Zip);
mail.Attachments.Add(attachment);
}
多亏了“Neils.R”的回答,我创建了一个静态C#函数来管理附件,并在超过1Mb时将其压缩。希望这对任何人都有帮助
public static Attachment CreateAttachment(string fileNameAndPath, bool zipIfTooLarge = true, int bytes = 1 << 20)
{
if (!zipIfTooLarge)
{
return new Attachment(fileNameAndPath);
}
var fileInfo = new FileInfo(fileNameAndPath);
// Less than 1Mb just attach as is.
if (fileInfo.Length < bytes)
{
var attachment = new Attachment(fileNameAndPath);
return attachment;
}
byte[] fileBytes = File.ReadAllBytes(fileNameAndPath);
using (var memoryStream = new MemoryStream())
{
string fileName = Path.GetFileName(fileNameAndPath);
using (var zipArchive = new ZipArchive(memoryStream, ZipArchiveMode.Create))
{
ZipArchiveEntry zipArchiveEntry = zipArchive.CreateEntry(fileName, CompressionLevel.Optimal);
using (var streamWriter = new StreamWriter(zipArchiveEntry.Open()))
{
streamWriter.Write(Encoding.Default.GetString(fileBytes));
}
}
var attachmentStream = new MemoryStream(memoryStream.ToArray());
string zipname = $"{Path.GetFileNameWithoutExtension(fileName)}.zip";
var attachment = new Attachment(attachmentStream, zipname, MediaTypeNames.Application.Zip);
return attachment;
}
}
public static Attachment CreateAttachment(string fileNameAndPath,bool zipIfTooLarge=true,int bytes=1DeflateStream!=Zip文件
(.Zip可以有多种压缩类型)可能与此重复。不过,我必须将ZipArchiveMode设置为Create。
public static Attachment CreateAttachment(string fileNameAndPath, bool zipIfTooLarge = true, int bytes = 1 << 20)
{
if (!zipIfTooLarge)
{
return new Attachment(fileNameAndPath);
}
var fileInfo = new FileInfo(fileNameAndPath);
// Less than 1Mb just attach as is.
if (fileInfo.Length < bytes)
{
var attachment = new Attachment(fileNameAndPath);
return attachment;
}
byte[] fileBytes = File.ReadAllBytes(fileNameAndPath);
using (var memoryStream = new MemoryStream())
{
string fileName = Path.GetFileName(fileNameAndPath);
using (var zipArchive = new ZipArchive(memoryStream, ZipArchiveMode.Create))
{
ZipArchiveEntry zipArchiveEntry = zipArchive.CreateEntry(fileName, CompressionLevel.Optimal);
using (var streamWriter = new StreamWriter(zipArchiveEntry.Open()))
{
streamWriter.Write(Encoding.Default.GetString(fileBytes));
}
}
var attachmentStream = new MemoryStream(memoryStream.ToArray());
string zipname = $"{Path.GetFileNameWithoutExtension(fileName)}.zip";
var attachment = new Attachment(attachmentStream, zipname, MediaTypeNames.Application.Zip);
return attachment;
}
}