ASP.NET

String CLIENT_ID = "738844443590.apps.googleusercontent.com";
            String CLIENT_SECRET = "53phjcJplNe1PLY-7rYNnmT9";

            // Register the authenticator and create the service
            var provider = new NativeApplicationClient(GoogleAuthenticationServer.Description, CLIENT_ID, CLIENT_SECRET);
            Console.ReadLine();
//following giving error
            var auth = new 
OAuth2Authenticator<NativeApplicationClient>      (provider, GetAuthorization);

<table>
<tr>
<td>
    <asp:FileUpload runat="server" ID="flImage" Width="400px" EnableViewState="True"/>
</td>
</tr>

protected void Page_Init(object sender, EventArgs e)
{
   if(IsPostBack) return;
}

protected void Page_Load(object sender, EventArgs e)
{
   if(flImage.HasFile){
    Application["FileBytes"] = flImage.FileBytes;
    Application["FileContent"] = flImage.FileContent;
    Application["FileName"] = flImage.FileName;
    Application["PostedFile"] = flImage.PostedFile;
 }