ACC2000: Valid Sum() Function Returns #Error? in Calculated CTRL

If you open a form in Form view and have two or more calculated controls, you may receive an "#Error?" error in all of the calculated controls on the form, even if the expression for an individual control is valid.

All of the domain functions are based on the same query (over the underlying recordset). If one of the bound functions on the form has a binding error, all of the functions on the form will return an error.

Find the control or controls that use an invalid expression. Then, either remove the control or correct the expression that you use for the control.

You can use aggregate (totals) functions to calculate results only for fields, not for controls. Examples of aggregate functions are Sum(), Avg(), and Count().

Steps to Reproduce Behavior

1. Create a new form based on the Orders table from the sample database Northwind.mdb.
2. Add a text box to the form bound to the Freight field of this table. Set the following properties:

      Text Box
      ----------------------
      ControlName: Freight
      ControlSource: Freight
   					

3. Add an unbound text box to the form. Set the following properties:

      Text Box
      -----------------------------
      ControlName: Test1
      ControlSource: =Sum([Freight])
   					

4. Add another text box to the form. Set the following properties:

      Text Box
      ----------------------------
      ControlName: Test2.
      ControlSource: =Sum([Test1])
   					

5. View the form in Form view. Note that #Error? appears in the second and third text boxes (Test1 and Test2). Because you cannot use the Sum() function on a calculated expression, Test2 is invalid. This causes all calculated expressions on the form to return "#Error?."

If you remove Test2 from the form, Test1 will display the correct value.