postback event and control-change event in ASP.NET

Question

I'ma a beginner in ASP.NET, just a question on event sequence on postback event and control event. Lets'say I have a button to submit a form and a dropdown on the form. So I selected sth to change the selected index first and then click the button, on the server, which event handler gets executed first? the button's click event handler or the dropdown's selectIndexChanged event handler?

Answer 1

You can enable Tracing to see order of event handling. More information at : https://blogs.msdn.microsoft.com/webdevelopertips/2009/06/11/tip-77-did-you-know-how-to-enable-page-level-tracing-for-your-asp-net-pages/

Also, if AutoPostBack is set to true on dropdown, then it will immediately post back when clicked.