using System;

using System.Web;

​

public class Program

{

    public void DownloadFile()

    {

        byte[] myBytes = null;

        //File.WriteAllBytes(_serverPath, myBytes);

        //

        //Different ways to download file.

        //WAY 1:

        HttpContext.Current.Response.AppendHeader("Content-Disposition", String.Format("attachment; filename={0}", "YourFileName"));

        HttpContext.Current.Response.ContentType = "application/pdf"; //"application/x-unknown/octet-stream"

        HttpContext.Current.Response.BinaryWrite(myBytes);

        //

        //WAY 2:

        //HttpContext.Current.Response.AppendHeader("Content-Disposition", String.Format("attachment; filename={0}", _fileName));

        //HttpContext.Current.Response.ContentType = "application/pdf";

        //HttpContext.Current.Response.OutputStream.Write(reportData, 0, reportData.Length);

        //

        //WAY 3: (ONLY IF YOU HAVE FILE PHYSICALLY ON THE MACHINE)

        //HttpContext.Current.Response.AppendHeader("Content-Disposition", String.Format("attachment; filename={0}", _fileName));

        //HttpContext.Current.Response.ContentType = "application/pdf";

        //Response.TransmitFile(Server.MapPath(_filePath));

        //

        var request = HttpContext.Current.Request;

        var fileCollection = request.Files;

        var anyExtraParamter = request.Params["anyExtraParamter"];

        for (int i = 0; i < fileCollection.Count; i++)

        {

            var postedFile = fileCollection[i];

        //Workbook workbook = new Workbook(postedFile.InputStream);

        }

         //Response.Flush();

         //Response.End(); //Throws System.Threading.ThreadAbortException: Unable to evaluate expression because the code is optimized or a native frame is on top of the call stack.

    }

}