Save As Dialog Box in Asp.Net Application

Question

Hi,

I want to implement Save As Dialog Box Asp.Net Application but there is no specific save dialog file and open dialog file in toolbox. I tried the following code to open Save as Dialog box
Response.ContentType = "image/jpeg";
Response.AppendHeader("Content-Disposition", "attachment; filename=image.jpg");
Response.TransmitFile(Server.MapPath("~/images/"));
But in this I am specifying specific file to save but i need to enter the file name dynamically by the user to save it in specified path.
Can anyone please help me how to resolve this problem.

Thanks in Advance
Pavani