Warnings to Make Them Wary

If you're in danger of this happening, it's time to bring out the heavy artillery by adding an error alert message as well. (You can always forgo the input message and just add the error alert message letting users know exactly what kind of behavior will and won't be tolerated in that cell.)

To add an error alert message that appears whenever the user tries to make an entry that violates the cell's data validation criteria, open the Data Validation dialog box and select the Error Alert tab. The settings on this tab enable you to

• Select a type of indicator to display in the alert dialog box (Stop, Warning, or Information) from the Styles drop-down list box.
• Enter a title for the warning in the Title text box (which appears in bold in the title bar of the custom alert dialog box).
• Type the text of the message in the Error Message list box (which appears in the body of the alert dialog box).

Don't select the Warning or Information type of error alert message unless you want it to be possible for your users to sidestep the validation settings and enter invalid data in the cell. (The Warning type allows this with its Yes button and the Information type with its OK button.) Only the default Stop type prevents users from going ahead and making invalid entries in the cell.

After adding an error alert message, whenever the user tries to enter something outside the bounds set by the cell's data validation settings, Excels beeps at them and then displays your custom error alert dialog box shows you how the custom error alert dialog box appears when you try to enter an invalid number (in this case, any whole number less than 5 or greater than 15 or any decimal number at all). When this Stop type of error alert appears, your users have two choices:

• Click Retry to have another go at entering the data (in hopes that the user can get it right this time).
• Click Cancel to clear the aberrant entry from the cell (and thus forget about the whole thing).