使用ASP.NET web窗体中的流返回可下载文件

Question

在ASP.NET MVC中，我可以做如下的事情来打开一个流:

 Stream strm1 = GenerateReport(Id);

return File(strm1, 
            "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
            "Report_" + reportId.ToString() + ".xlsx");

请注意我是如何传递 strm1 的，这是一个流。然后我可以把它命名Report_...XLSX 如上例所示。

有没有类似的方法可以使用c#来处理asp.net web表单。

Answer 1

或者，如果您已准备好要写入的流，只需将其复制到响应流中：

Response.Clear();
Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
Response.AddHeader("Content-Disposition", "attachment; filename={your file name}");
Response.OutputStream.Write(stream, 0, stream.length);
Response.End();

添加相同的代码只是为了可见性

Answer 2

我使用此扩展名将流作为可下载文件发送：

public static class ToDownloadExtention
{
   public static void ToDownload(this Stream stream, string fileName, HttpResponse response)
    {
        response.Clear();
        response.ContentType = "application/octet-stream";
        response.AddHeader("Content-Disposition", string.Format("attachment; filename={0}", fileName));
        stream.CopyTo(response.OutputStream);
        response.End();
    }
}

用法是：

var stream = new MemoryStream();

stream.ToDownload("someFileName.ext",Response);

Answer 3

如果文件在您的网站文件夹中，您可以使用TransmitFile或WriteFile。

string fileName = string.Format("Report_{0}.xlsx", reportId);
Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
Response.AddHeader("Content-Disposition", 
   string.Format("attachment; filename={0}", fileName));
Response.TransmitFile(fileName);
Response.End();

如果你的数据已经在内存中，你需要这个方法，它以块的形式写入响应。

Stream stm1 = GenerateReport(Id);
Int16 bufferSize = 1024;
byte[] buffer = new byte[bufferSize + 1];

Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
Response.AddHeader("Content-Disposition", 
    string.Format("attachment; filename=\"Report_{0}.xlsx\";", reportId));
Response.BufferOutput = false;
int count = stm1.Read(buffer, 0, bufferSize);

while (count > 0)
{
    Response.OutputStream.Write(buffer, 0, count);
    count = stm1.Read(buffer, 0, bufferSize);
}