Code in a sub form

[Jade]

I have a form and a sub form and I need to write an If Statement in the subform. If someone chooses an item from a drop down list say "field 1", I need to force the user to input data into one other field say "field 2". How is this done?

Thank you for your help

 

[Jon Holmes]

Jade,

This depends on the location of the controls. If both are on the subform then it's pretty simple. Attached to the subform's BeforeUpdate property would be a few lines like;
If IsNull(Me.Field2) Then
MsgBox "Please complete field 2"
Cancel = True
End If
The Cancel = True statement will stop the record from updating until something is placed in Field 2.
If Field 1 is on the main form and field 2 on the sub form then it gets a little trickier. eg. If the sub form lists multiple records against the main form. Different strategies would be employed depending on your needs.

Jon