Add filter to FileUpload Control.

Question

How to add filter to the fileupload control in asp.net? I want a filter for Word Template File (.dot).

Answer 1

Check the filename of the uploaded file serverside:

FileUpload1.PostedFile.FileName

Unless you want to use java or something similar on the client, there's really not much you can do for filtering uploaded files before they're sent to the server.

Answer 2

        string fileName = fuFiles.FileName;

        if(fileName.Contains(".dot"))
        {
            fuFiles.SaveAs(Server.MapPath("~/Files/" + fileName));
        }

Answer 3

If you mean to filter the file extensions client/side, with the standard browser's file selector, isn't possible. To do that you have to use a mixed type of upload, such as SWFUpload, based on a flash uploader system (that's a really nice techinque: it allows you to post more than a file at time).

The only thing you can do in standard mode is to filter the already posted file, and I suggest to use System.IO.Path namespace utility:

if (Path.GetExtension(upFile.FileName).ToUpper().CompareTo(".DOT") == 0) 
{
    /* do what you want with file here */ 
}

Answer 4

You could also do a javascript alternative to filtering it server side (you'd probably want to do that as well) but this saves the client from spending the time waiting on an upload to finish just to find out it was the wrong type.

http://javascript.internet.com/forms/upload-filter.html

So basically you just run a javascript function on submit that parses off the extension of the uploaded file and gives them an alert if its not of the right type.

You could also use document.forms[0].submit(); instead of passing the form reference through (as ASP.NET really only uses a single form (unless your doing something funky))