Upload multiple files to Google Drive using C# in ASP.Net

Hello sir,

I have used your google drive api code, it is working fine for single document but i want to upload document as well without size restriction and without asking for access everytime to upload docs.

I have attached my code for your reference.

kindly reply for that. 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using ASPSnippets.GoogleAPI;
using System.Web.Script.Serialization;

public partial class Upload : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        GoogleConnect.ClientId = "988940200336-8klssk61lg30a19i20dbkovg6n3v3u8c.apps.googleusercontent.com";
        GoogleConnect.ClientSecret = "JlxVnVuv-Cc5_uir7HZokSe_";
        GoogleConnect.RedirectUri = Request.Url.AbsoluteUri.Split('?')[0];
        GoogleConnect.API = EnumAPI.Drive;
        if (!string.IsNullOrEmpty(Request.QueryString["code"]))
        {
            string code = Request.QueryString["code"];
            string json = GoogleConnect.PostFile(code, (HttpPostedFile)Session["File"], Session["Description"].ToString());
            GoogleDriveFile file = (new JavaScriptSerializer()).Deserialize<GoogleDriveFile>(json);
            tblFileDetails.Visible = true;
            lblTitle.Text = file.Title;
            lblId.Text = file.Id;
            imgIcon.ImageUrl = file.IconLink;
            lblCreatedDate.Text = file.CreatedDate.ToString();
            lnkDownload.NavigateUrl = file.WebContentLink;
            if (!string.IsNullOrEmpty(file.ThumbnailLink))
            {
                rowThumbnail.Visible = true;
                imgThumbnail.ImageUrl = file.ThumbnailLink;
            }
        }
        if (Request.QueryString["error"] == "access_denied")
        {
            ClientScript.RegisterClientScriptBlock(this.GetType(), "alert", "alert('Access denied.')", true);
        }
    }
    protected void btnUpload_Click(object sender, EventArgs e)
    {
        foreach (var file in FileUpload1.PostedFiles)
        {
            Session["File"] = file;
            Session["Description"] = txtDescription.Text;
            GoogleConnect.Authorize("https://www.googleapis.com/auth/drive.file");
        }
        
    }


    public class GoogleDriveFile
    {
        public string Id { get; set; }
        public string Title { get; set; }
        public string OriginalFilename { get; set; }
        public string ThumbnailLink { get; set; }
        public string IconLink { get; set; }
        public string WebContentLink { get; set; }
        public DateTime CreatedDate { get; set; }
        public DateTime ModifiedDate { get; set; }
    }
}