ERR: Not a Numeric Expression

• Microsoft Visual FoxPro for Windows, version 3.0
• Microsoft FoxPro for Windows, versions 2.5x, 2.6x
• Microsoft FoxPro for MS-DOS, versions 2.0, 2.5x, 2.6x

SYMPTOMS

You receive the error message "Not a numeric expression" after any of four types of @ ... GETs: buttons, radio buttons, popups, and list boxes.

CAUSE

The FoxPro for Windows "Developer's Guide" for versions 2.5x and 2.6x states on page B-26 that the error "Not a numeric expression" occurs when "An attempt was made to use the SUM command on a non-numeric field."

Another cause for this error message is using a variable that has not been initialized after being declared in a button, radio button, popup, or list box.

RESOLUTION

If a variable is declared, but not initialized, it contains the value of false (.F.). If you then use this variable as the variable for specific types of @ ... GET commands, you will see the "Not a numeric expression" error when you run the code.

The solution is to initialize the variable to a number, or to not declare the variable at all.

MORE INFORMATION

Steps to Reproduce Behavior

1. Place the following code in a program called TEST.PRG:

         CLEAR
         RELEASE ALL
         PUBLIC var1, var2, var3, var4
         DIMENSION myarray(4,1)
         myarray(1,1)="LIST1"
         myarray(2,1)="LIST2"
         myarray(3,1)="LIST3"
         myarray(4,1)="LIST4"
   

         DEFINE WINDOW main AT 0,0;
            SIZE 17.875,70.286 ;
            FONT "MS Sans Serif", 8 ;
            FLOAT ;
            NOCLOSE ;
            MINIMIZE ;
            SYSTEM
   
         ACTIVATE WINDOW main
   
         @ 4.500,3.429 GET var1 ;
            PICTURE "@*HN BUTTON1; BUTTON2" ;
            SIZE 1.625,11.875,0.500 ;
            DEFAULT 1
   
         @ 6.688,3.429 GET var2 ;
            PICTURE "@*RVN RADIO1; RADIO2" ;
            SIZE 1.063,7.750,0.250 ;
            DEFAULT 1
   
         @ 1.375,42.857 GET var3 ;
            PICTURE "@^ POPUP1; POPUP2" ;
            SIZE 1.500,15.125 ;
            DEFAULT 1
   
         @ 4.438,44.714 GET var4 ;
            PICTURE "@&N" ;
            FROM myarray ;
            SIZE 4.500,17.000 ;
            DEFAULT 1
   
         READ CYCLE
   
         RELEASE WINDOW main
   
   

2. Run the program. The "Not a Numeric Expression" error will occur.

3. Choose the Ignore button. The error will occur again for each @ ... GET defined in the program. If you keep choosing Ignore, the program will run through to the end.

Workaround

There are two ways to resolve this problem:

• Remove the line "PUBLIC var1, var2, var3, var4" from the program, and run it again. It should work as expected.

  -or-

• After declaring them, initialize VAR1, VAR2, VAR3, and VAR4 to 1. The program should no longer display the error.

REFERENCES

"Language Reference," version 2.5 (MS-DOS, Windows), pages L3-31 to L3-126