2
我在MVC3中使用心爱的DotNetZip存档库来生成Zip文件,其中包含存储在数据库中的二进制文件的.png图像。然后我将流生成的Zip文件流出供用户下载。 (我在保存到数据库之前验证图像数据,因此您可以假设所有图像数据都是有效的)。创建并传输图像存档zip文件以供下载C#
public ActionResult PictureExport()
{
IEnumerable<UserPicture> userPictures = db.UserPicture.ToList();
//"db" is a DataContext and UserPicture is the model used for uploaded pictures.
DateTime today = DateTime.Now;
string fileName = "attachment;filename=AllUploadedPicturesAsOf:" + today.ToString() + ".zip";
this.Response.Clear();
this.Response.ContentType = "application/zip";
this.Response.AddHeader("Content-Disposition", fileName);
using (ZipFile zipFile = new ZipFile())
{
using (MemoryStream stream = new MemoryStream())
{
foreach (UserPicture userPicture in userPictures)
{
stream.Seek(0, SeekOrigin.Begin);
string pictureName = userPicture.Name+ ".png";
using (MemoryStream tempstream = new MemoryStream())
{
Image userImage = //method that returns Drawing.Image from byte[];
userImage.Save(tempstream, ImageFormat.Png);
tempstream.Seek(0, SeekOrigin.Begin);
stream.Seek(0, SeekOrigin.Begin);
tempstream.WriteTo(stream);
}
zipFile.AddEntry(pictureName, stream);
}
zipFile.Save(Response.OutputStream);
}
}
this.Response.End();
return RedirectToAction("Home");
}
此代码可用于上传和导出一(1)张图片。但是,将多个图像上传到数据库并尝试将其全部导出后,生成的Zip文件将只包含最新上传图像的数据。所有其他图像名称都将出现在zip文件中,但它们的文件大小将为0,它们只是空文件。
我猜我的问题与MemoryStreams有关(或者我错过了一些简单的东西),但是据我所知,通过代码遍历,图像被从数据库中提取出来被成功添加到zip文件中...
工作!谢谢!!! – user1449244