i am trying to check the text box for nulls once the user tabs over the text box. i do not want it to check for nulls when i click on okay. here is code. do i need to setfocus so it will go back to the text box?

Private Sub txtArrivalDate_ AfterUpdate()

Dim ArrivalDate As Date

ArrivalDate = txtArrivalDate. Value

If IsNull(ArrivalD ate) Then MsgBox ("Please enter a valid date.")

End Sub