i vote for my idea if the datetime value changes. if it is a constant then i vote for jmc. "easiest to implement" scares me.

btw - don't use focus. if you need to give focus to a control use .Select

Code:
        Dim s As String = "7/29/09 08:00"
        myPicker.Format = DateTimePickerFormat.Custom
        myPicker.CustomFormat = "MM/dd/yyyy   hh:mm:ss tt"
        If DateTime.TryParse(s, myPicker.Value) Then
            'string was a valid datetime format
            Debug.WriteLine("OK " & myPicker.Value.ToString)
        Else
            'bad datetime
            Debug.WriteLine("BAD " & myPicker.Value.ToString)
        End If
        myPicker.Select()