There is two ways:
1st:
int index = Convert.ToInt32(e.CommandArgument);
string url = GridView1.Rows[index].Cells[13].Text;
Response.Redirect(url)
And
2nd:
int index = Convert.ToInt32(e.CommandArgument);
string url = GridView1.Rows[index].Cells[13].Text;
FileInfo file = new FileInfo(url);
if (file.Exists)
{
Response.Clear();
Response.ClearHeaders();
Response.ClearContent();
Response.AddHeader("content-disposition", "attachment; filename=" + fileName);
Response.ContentType = "application/octet-stream";
Response.AddHeader("Content-Length", file.Length.ToString());
Response.WriteFile(file.FullName);
Response.End();
}
else
{
Response.Write("This file does not exist.");
}
Hope it works!
--Amit