Downloading .mp4 using IE saves as .data

Question

I have a .NET project, where I have a direct link to download .mp4 to users hard drive. It works fine in chrome, but in IE, it saves it as a .data file. Does anyone know how I can fix this?

In my .aspx page I use this link:

<asp:hyperlink Visible="false" id="dlVideo" Font-Size="8pt" NavigateUrl='<%# Eval("VideoName", "~/Workshops/Refology/Get.aspx?FileName={0}&OrigName=" + Eval("FirstName") + "&CamperName=" + Eval("lastname") + "&Topic=" + Eval("Topic"))%>' runat="server" Text='<%# IIf(Eval("VideoName") Is DBNull.Value, "", "Video")%>'></asp:hyperlink>

And in the Get.aspx.cs page is this:

protected void Page_Load(object sender, EventArgs e)
{
    string videoName = Request.QueryString["FileName"];
    string OriginalName = Request.QueryString["OrigName"];
    string PersName = Request.QueryString["CamperName"];
    string Topic = Request.QueryString["Topic"];
    string FinalName = PersName + "-" + OriginalName + "-" + Topic;

    Response.Clear();
    Response.ContentType = "video/mp4";
    Response.AddHeader("Content-Disposition", "attachment; filename=" + FinalName);
    Response.TransmitFile(Server.MapPath("~/contents/published/" + videoName));
    Response.Flush();
    Response.End();
}

Answer 1

Taking a guess, but chances are it's because you're exempting the extension from your filename in the Content-Disposition header. Also, if your FinalName has spaces in it, your header is going to be messed up; you should probably escape it. e.g.

/* ... */

var contentDisposition = new System.Net.Mime.ContentDisposition("attachment")
{
    FileName = FinalName + ".mp4"
}:

// Properly encode header using ContentDisposition class.
Response.AddHeader("Content-Disposition", contentDisposition.ToString());

The ContentDisposition class can build the header for you encoding it as necessary.