Microsoft KB Archive/90802

PRB: "Invalid Use of Null Alert" Error with Eval() Function

Article ID: Q90802
Creation Date: 22-OCT-1992
Revision Date: 19-SEP-1996 The information in this article applies to:

Microsoft Access versions 1.0, 1.1, 2.0, 7.0

SYMPTOMS

Moderate: Requires basic macro, coding, and interoperability skills.

If you use the Eval() function on a field that does not contain a value, you may receive the following error message:

   Invalid Use of Null Alert

STATUS

This behavior is by design.

MORE INFORMATION

Steps to Reproduce Behavior

In Microsoft Access for Windows 95 version 7.0:

Create a form (Form1) with a text box (text0).
View the form in Form view.
Press CTRL+G to bring up the Debug Window.
Type the following line in the Debug Window:
```
      = Eval("Forms!Form1!Text0").
```
Note that you receive the error message "Invalid Use of Null Alert."

In Microsoft Access versions 1.x and 2.0:

Create a form (Form1) with a text box (text0).
View the form in Form view.
Open a module.
Type the following line in the Immediate window:
```
      stForm$ = Eval("Forms!Form1!Text0")
```
Note that you receive the error message "Invalid Use of Null Alert."

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Additional reference words: 1.00 1.10 2.00 7.00
KBCategory: kbprg kberrmsg
KBSubcategory: PgmOthr