How to set cursor focus to a textbox?

See more:

C#

VS2010

How can i focus cursor on sepecific textbox.

I tried using

textBox1.Select();
This is working when on form load. But when i load
item in the listbox does not select the textbox.

Also i tried using

textBox1.Focus();
Its the same.

What i want is when i click a button or lets say when i press
Save button and show dialogbox of Yes or No ,
When i press Yes and save the file ,cursor will
Go to the specific textbox. textBox1.

What I have tried:

Tried using this:

Select();
Focus();