Web Forms :: Controlling Focus On Form With AutoPostBack TextBoxes?

I have a form with several textboxes. All of these have AutoPostBack="True".

My problem is that the focus disappears to goodness knows where after each postback. The behaviour I would like to enforce is as follows,

If the user hits the Enter or Tab key after filling in a textbox then the focus should go to the next field on the form (to be explicitly specified in my code).

If the user clicks on textbox X after filling in textbox A then the focus should go to textbox X after postback, even if it is not the next in the list.

In other words, I want the form to behave in the way that most users would intuitively expect.

I have Googled for potential solutions to the loss of focus after postback but the few that I have found were many years old and I am unsure that the advice is still relevant for ASP.NET 4.0. Some of these old solutions also appeared to be invalid for browsers other than IE. What is the current best practice for handling this issue?

BTW, VB.NET solutions are preferred though I will also be happy to accept C# suggestions (which I would run through a code converter). Note that I have a single sub in my code for handling the TextChanged events for all my textboxes. This means that I have to use the following code to work with the textbox that has called the sub.

Dim CurrentTextBox
As
TextBox =
DirectCast(sender,
TextBox)

If addressing the focus problem means that I have to have individual TextChanged event subs for each textbox then so be it, but I prefer the simplicity of my current single sub approach.