Download file code not working for firefox and IE - asp.net

Question

I have created a code for downloading images. It works fine if the file name has no special characters or the punctuation marks. But I found an issue when the file name contains other language's character or ',' in the file name.
My code is :
private void AddFile(SPFile file)
{
try
{
System.IO.FileInfo fileInfo = new FileInfo(file.Name);
string filename = GeneralMethods.MakeValidFileName(file.Name);
filename += fileInfo.Extension;
byte[] obj = (byte[])file.OpenBinary();
Response.ClearContent();
Response.ClearHeaders();
Response.AppendHeader("Content-Disposition", "attachment; filename= " + filename);
Response.ContentType = "application/octet-stream";
if (Response.IsClientConnected)
Response.BinaryWrite(obj);
Response.Flush();
Response.Close();
}
catch (Exception ex)
{
}
finally
{
}
}
To avoid the other language's characters and other punctuation marks in the file name I created one method to replace non English character to blank.
public static string MakeValidFileName(string name)
{
Regex rgx = new Regex("[^a-zA-Z0-9 -]");
return rgx.Replace(name, "");
}
In my scenario, I have two files 'xäbace 11,5 hm' & 'Png file'. I am able to download these files in Chrome but not able to download in IE & Firefox. And one more thing, the file is downloaded in Firefox but without extension. i.e. the file gets downloaded and after completing if I add extension to that file it works fine.
What should I do to tackle the issue?

Answer 1

Sincerely, I don't understand ASP.
But it seems you are permitting spaces in file names. You should avoid it, because some browsers will force URL encode of the filename, replacing spaces by %20 and messing up with the file path.
Also, in some languages (PHP) spaces in file names can in some cases, force the MIME type to text/html.
For many reasons you should the, avoid spaces in files to be downloaded or just used in the web.