Refresh textbox with a MsgBox()

[FEOL]

Hi.
In a web form I have this code in VB, on the button_Click event:

Text1.text = "1"
Text2.text = "2"
MsgBox("OK?", MsgBoxStyle.Information, "Cancel")

The MsgBox displays but the textboxes doesn't refresh. What am I missing?
Thanks.

(Sorry, I posted in the wrong forum, is VB not c#)