Control to be selected after post back of dotnet page written in VB

I have a page of web site written in Visual Basic for Dot Net. When a text box in this case a obout text box autopost back and the page returns the next control should get selected. But the cursor goes to the first control on the page. There is a code written on the page to be executed on Post back. After execution of the code the control should be selected I wish to have a code so that subsequent control is selected. Rest all the code is working fine