So I adapted a bit Ben's solution, and I add hidden text box, and update its value before calling the do Post Back method.
The Web Forms data-binding architecture allows you to bind control properties to a data source, making it easy to display data on the page. To enhance the Web Forms page you have created, you might want to explore some of the following ideas: Walkthrough: Creating Read-Only Data Access in a Web Forms Page | Introduction to ADO.
However, the data-binding architecture does not support updates — that is, data binding is one-way in Web Forms pages. NET Connection Design Tools | Introduction to Data Command Objects in Visual Studio | Executing a Data Command That Returns a Result Set | Executing Updates or Database Commands using a Data Command | Setting and Getting Data Command Parameters | Concurrency Control in ADO.
I set the value on the hidden textbox but I do the postback on the button.
All my internet searches actually shows how to do this using background thread - it is the approach that needs to be taken in a proper programming context, however there are times when you just want to do something quick & dirty or you want to augment an existing app / port where you don't want to introduce new elements.