The value I input into textbox1 I want to add into
combobox1. But first I want the code to check combobox1
first to see if the value exists, if it does then the code
stops, if not then add it in.

I have this already but am stuck:

If combobox1.? = textbox1.text Then
GoTo end
Else:
cmbRollNumber.AddItem (txtBAID.Text)
End If