I am trying to create a simple WebForm in Visual Studio 2017. I have a textbox and I have to catch "Leave" event on it, but these are the only events available:

I've been searching for similar questions and problems but I did not find any solutions.
I am trying to create a simple WebForm in Visual Studio 2017. I have a textbox and I have to catch "Leave" event on it, but these are the only events available:

I've been searching for similar questions and problems but I did not find any solutions.
There is no Leave event because ASP.NET runs on Server while the user's "leave" happens on the client. You could handle the blur event in JavaScript and then do a post back. Very nice solution is in this SO answer.
This is normal behavior, you're working with a System.Web.UI.WebControls.TextBox.
It doesn't have a Leave event since it's a Web UI control. If you want a Leave event, you'll have to use Javascript (note that this will be Client-Side).