File Upload and Export option with VS 2015

Hello,

I am using Visual Studio 2015, ASP.NET framework : 4.6.1

I am trying to do file upload and export to excel. both things were working fine in VS2010 but same form, same codes are not working on VS2015.

We already configured the following :-

In webconfig :-

<appSettings><addkey="ValidationSettings:UnobtrusiveValidationMode"value="None"/></appSettings>

In Page :-

<Triggers><asp:PostBackTriggerControlID="SaveBtn"/></Triggers>

In Page Header :-

EnableEventValidation="false"

My codes are not generating any error, but even not working as expected in VS2015. If I just copy-paste the same page/code in VS2010 it will start working.

Remember : my scriptmanager is allocated in master file.