Form to add/edit rows in a table with a multi-field primary key

[JohnnyOz]

I'm very new to Access and I want to do something I hope is quite simple. I have just one table, which has a three-field primary key. I want to create a form which allows easy adding of rows and updating of rows without using the forward/backward buttons at the bottom. I want to use combo boxes and a 'Save' button.

The problem is that I want the three key fields to be at the top of the form as combo-boxes. If values are selected which correspond to an existing row I want the rest of the form fields filled with the row data and for the row to be updated by means of the 'Save' button. If the three combo boxes are set to values which don't correspond to an existing row I want the remaining fields to be blank and for the row to be created when the 'Save' button is pressed.



Quite simple, really, but I can't seem to get it to work. I have set the table up with the required key and I have placed the combo boxes on the form with acceptable values in a list. The problem is that I can't get the form to update when the combo boxes are changed. It seems easy enough when there's just one field in the primary key, but when I try it with my three-field primary key I get errors saying that I am attempting a CancelUpdate without having previously issued an Edit or AddNew, or something like that.

Any ideas?

[RuralGuy]

Why do you feel you need all three fields in the PrimaryKey?