Question

我有一个简单的ASP.NET网页，使用VB和文件上传控件。用户将上传.xls，并在项目目录中使用新格式和一些计算创建新的.xls文件。此文件保存，打开和显示没有问题。

在此按钮单击事件中，我希望新创建的文件下载到用户的浏览器/下载文件夹。当Response.WriteFile与Response.End一起使用时，.xls文件正确下载...但是有一个线程中止异常被捕获，并且在处理Response.WriteFile行之后没有任何内容，即使我把它放在catch语句中（即我有一个标签，我想告诉用户然后显示该文件已成功下载。

以下是最常用的初始代码：

Protected Sub btnUpload_Click(sender As Object, e As EventArgs) Handles btnUpload.Click
        If fuReport.HasFile Then

'All report processing occurs & report is created without issue

    Try
        Response.Clear()
        Response.AddHeader("Content-Disposition", String.Format("attachment; filename={0}", strReportName))
        Response.ContentType = "application/vnd.ms-excel"
        'Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
        Response.WriteFile(strReportName)
        Response.End()
        lblResult.Text = "Report was successfully downloaded."
     Catch
        lblResult.Text = "Testing1."
     Finally
        lblResult.Text = "Testing2."
        fuReport = New FileUpload()
     End Try
    End If
    End Sub

我已经看到了针对.xls文件的ContentType的一些不同建议。上面的两种内容类型都将下载该文件，但不处理Catch或Finally语句中的任何内容。 lblResult仍然会写道：“请等待你的报告处理......”

我在网上发现问题在于Response.End（）。根据{{3}}，我将其替换为

HttpContext.Current.ApplicationInstance.CompleteRequest()

这引起了一个新问题。我的.xls文件会下载，但它似乎显示乱码，其次是一些aspx页面内容。此处，即使标签未在网页上更改，也会正确列出标签。我没有足够的声誉来包含屏幕截图，但这是Excel文件显示的内容之一：

ˆdQ_9€`Èb/ecÈ¢l†=gÊC\Œ¬ÀxbY”Â…‘#ˆ,ör6ˆ,Ê…8ëY8ÖæBô?³2º‹CÓž€|^î¯{{<xJñ¯ªç2,FÑ+sbŸ£å›q³žcm"9ŸÛÆ…îâpoŸûñä_õ¥1K×Ê1Ü–‘äŒä‚$‹’,ÊÞÿ?ëY9ÖÎÉºa 9†7(Æ‘E‰c<µŠ$wïå¼Q9çƒìù93vì£Þ¾ŠõXè.î·ÛúÏöX;`>¸w!‚™•óÂ‘#Ž,8²(ãÞqÖ3q¬M¥dÝ ‚Â7VE¾‰`|mä^@Y”°çÞÌØZXß²‹O•½në›×å=än½‘°i”EàqÅ^Ê6‹²(×›õìks   žú¦¸Ð½µW§îo[‚‡ÚGÈýz3·!dÑ„@ dq€E9õ×3lfl%Ø™^Vv
@ÈB{)[²èïmÖ³l¬…8óI–½-?o{ÖÎ¤,÷Ä²hC ²ØKÙ²hmïÕÎžâ}û‡.vÝÌznµ³ð±Lâc¹7†E  ÜOpÁÅ^ÎÆEyüæ=£ÆÚÄÏnïýúº·7åå‡v³Í[;Î¿Šþ•PˆÃp%*0B!ö
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<!DOCTYPE html> 

<html xmlns="http://www.w3.org/1999/xhtml"> 
<head id="Head1"><title>    

</title>    
    <script type="text/javascript"> 
        function changeLabel(){ 
            document.getElementById("lblResult").innerHTML = "Please wait while your report is processed...";   
        }   
    </script>   
</head> 
<body>  

    <form method="post" action="Uploader.aspx" id="form1" enctype="multipart/form-data">    
<div class="aspNetHidden">  
<input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="+yve+0TnTzr8dZbqET3gRkZx/Pw9iGFmDqDyyfeTPMoXlPTPVgX3FrRUhTd3lBZE0DkzyUKzhXOi6MqTdxe1jnYL+mdzQiyoaM5w5cv9vij3X1xtsW8P1zACrDj6IqUK87n3GcwFtdHCCblAdgFI8nPQZsJnRv9w8lNIurcrbfad534ICOt8S/++vRi9+s91DFi3woIbFMyxw3rvbUPQwg==" />    
</div>  

<div class="aspNetHidden">  

    <input type="hidden" name="__VIEWSTATEGENERATOR" id="__VIEWSTATEGENERATOR" value="C153B6F1" />
    <input type="hidden" name="__EVENTVALIDATION" id="__EVENTVALIDATION" value="c3fKPUwILazJv1aW60quCxYtkspAHgetjdwMb7ugaEBN7qnUTTL7SrAVizVMaqXPAPqmyhDV0rtT1upkWYH9eOzqHjjmjvr9ZHty08BHB9OD/fCIuF8ExZbOqpiXOdGA" />


 </div> 


  <div> 
        <input type="file" name="fuReport" id="fuReport" style="width:306px;" />    
        <br />  
        <span id="lblResult">Report was successfully downloaded.</span> 
        <br />          
        <input type="submit" name="btnUpload" value="Upload" onclick="changeLabel();" id="btnUpload" /> 
    </div>      
    </form> 
</body> 
</html>

然后我尝试用HTTPContext替换所有的响应代码，如下所示：

HttpContext.Current.Response.ClearContent()
HttpContext.Current.Response.AddHeader("Content-Disposition", String.Format("attachment; filename={0}", strReportName))
HttpContext.Current.Response.ContentType = "application/vnd.ms-excel"
HttpContext.Current.Response.Write(strReportName)
HttpContext.Current.ApplicationInstance.CompleteRequest()

这也会下载.xls文件，但会显示网页的图形表示。再次，我无法发布图片，但Excel文件打开以显示带有文本的按钮，上传和放大表示：

报告已成功下载。

我已经研究了这个没有解决方案的HOURS。我尝试将这个特定的代码从try / catch / finally中拉出来，因为其他人已经取得了成功，但这也无济于事。

有没有人知道我如何正确地让浏览器下载.xls文件和我的NewReport的实际内容而不是它包含来自aspx页面的信息？

Answer 1

I like to use BinaryWrite, something like this:

Dim ms As New IO.MemoryStream
xWB.Write(ms)
Dim bytes As Byte() = ms.ToArray
Response.ContentType = "application/vnd.ms-excel"
Response.AddHeader("content-disposition", "attachment;filename=" & strReportName)
Response.BinaryWrite(bytes)
Response.Flush()
Response.End()

Answer 2

我放弃了自动执行这两个过程的想法。我添加了一个“下载”按钮，该按钮仅在成功处理报告后才会显示。在点击事件的下载按钮上，我有excel文件下载。这比我想要的还要多一点，但它完成了工作。

Protected Sub btnUpload_Click(sender As Object, e As EventArgs) Handles btnUpload.Click
If fuReport.HasFile Then
    Try        
        'All report processing occurs & report is created without issue   
        lblResult.Text = "Report was successfully processed."
        btnDownload.Visible = True  
    Catch
        lblResult.Text = "An error occurred. Please try again."
    Finally
        fuReport = New FileUpload()
    End Try
  Else
        lblResult.Text = "Please select a report to upload."
    End If
End Sub

Protected Sub btnDownload_Click(sender As Object, e As EventArgs) Handles btnDownload.Click
        Response.AddHeader("Content-Disposition", String.Format("attachment; filename={0}", strReportName))
        Response.ContentType = "application/vnd.ms-excel"
        Response.WriteFile(strReportName)
        Response.End()
    End Sub
End Class

使用Response.WriteFile下载.xls文件，下载包含网页内容

2 个答案: