How do you stream an Excel 2007 or Word 2007 file using asp.net and c#

Question

I'm working on a web app and need to stream various files. I can do pdfs, images, and older Office documents. However, when I try to do with 2007 documents, it breaks. Here is my code:

    Response.Buffer = true;
    Response.Clear();
    Response.ClearContent();
    Response.ClearHeaders();
    switch (FileExtension.ToLower())
    {
        case "pdf":
            Response.ContentType = "application/pdf";
            break;
        case "doc":
            Response.ContentType = "application/msword";
            break;
        case "docx":
            Response.ContentType = "application/vnd.ms-word.document.12";
            break;
        case "xls":
            Response.ContentType = "application/vnd.ms-excel";
            break;
        case "xlsx":
            Response.ContentType = "application/vnd.ms-excel.12";
            break;
        default:
            Response.ContentType = "image/jpeg";
            break;
    }
    Response.BinaryWrite(buffer);

The error that I get is:

An invalid character was found in text content. Error processing resource 'http://DomainName/GetFile.aspx...

PK

Any suggestions?

Answer 1

According to a brief web search, the correct mime types for word and excel are:

application/vnd.openxmlformats-officedocument.wordprocessingml.document
application/vnd.openxmlformats-officedocument.spreadsheetml.sheet

http://www.bram.us/2007/05/25/office-2007-mime-types-for-iis/

Edit:

The following simplified sample works for me. It is different from yours in that it uses a generic handler instead of a web form (which is more appropriate for something like this anyway).

To test it, make sure there is an excel 2007 file named Book1.xlsx in the top level folder of the application.

DownloadSpreadsheet.ashx:

<%@ WebHandler Language="C#" Class="DownloadSpreadsheetHandler" %>

using System;
using System.Web;
using System.IO;

public class DownloadSpreadsheetHandler: IHttpHandler {

    public void ProcessRequest (HttpContext context) {
        context.Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
        string path = context.Server.MapPath("~/Book1.xlsx");
        using (FileStream spreadsheet = File.OpenRead(path))
        {
            CopyStream(spreadsheet, context.Response.OutputStream);
        }
    }

    public bool IsReusable {
        get {
            return false;
        }
    }

    private static void CopyStream(Stream input, Stream output)
    {
        byte[] buffer = new byte[32768];
        while (true)
        {
            int read = input.Read(buffer, 0, buffer.Length);
            if (read <= 0)
                return;
            output.Write(buffer, 0, read);
        }
    }

}

Answer 2

For csv format files that we want Excel to be used to open, we are using: Response.ContentType = "application/msexcel";

Perhaps we get away with this because it is not a true xls file, however.