Some time you need to download the file from the URL then follwing code can help u out.
private void downloadURL(string fileURL)
{
//::->STEP
//::->Step -1 :::->Get filename
//::->Step -2 :::->Adding Headeres
//::->Step -3 :::->Set the Content Type
//::->Step -4 :::->Tansmit the file
//::->Step -5 :::->End of the Response
string name = Path.GetFileName(fileURL);
// ::->Get filename
string fileName = Path.GetFileName(fileURL);
// ::-> Adding Headeres
Response.AddHeader("Content-disposition", "attachment; filename=" + fileName);
//::-> Set the Content Type
Response.ContentType = "application/octet-stream";
//::-> Tansmit the file
Response.TransmitFile(fileURL);
//::-> End of the Response
Response.End();
}