Excel's Formula - sisman

Chapter 19: Conditional Formatting and Data Validation 547
Any Value: Selecting this option removes any existing data validation. Note, however,
that the input message (if any) still displays if the check box is selected in the Input
Message tab.
Whole Number: The user must enter a whole number. You specify a valid range of whole
numbers by using the Data drop-down list. For example, you can specify that the entry
must be a whole number greater than or equal to 100.
Decimal: The user must enter a number. You specify a valid range of numbers by using
the Data drop-down list. For example, you can specify that the entry must be greater
than or equal to 0 and less than or equal to 1.
List: The user must choose from a list of entries that you provide. This option is very useful,
and I discuss it in detail later in this chapter (see the section “Creating a drop-down list”).
Date: The user must enter a date. You specify a valid date range by using the Data dropdown
list. For example, you can specify that the entered data must be greater than or
equal to January 1, 2010, and less than or equal to December 31, 2010.
Time: The user must enter a time. You specify a valid time range by using the Data
drop-down list. For example, you can specify that the entered data must be greater than
12:00 p.m.
Text Length: The length of the data (number of characters) is limited. You specify a valid
length by using the Data drop-down list. For example, you can specify that the length of
the entered data be 1 (a single alphanumeric character).
Custom: To use this option, you must supply a logical formula that determines the validity
of the user’s entry. (A logical formula returns either TRUE or FALSE.) You can enter
the formula directly into the Formula control (which appears when you select the Custom
option), or you can specify a cell reference that contains a formula. This chapter contains
examples of useful formulas.
The Settings tab of the Data Validation dialog box contains two other check boxes:
Ignore Blank: If checked, blank entries are allowed.
Apply These Changes to All Other Cells with the Same Settings: If checked, the changes
you make apply to all other cells that contain the original data validation criteria.
It’s important to understand that even with data validation in effect, the user can enter invalid
data. If the Style setting in the Error Alert tab of the Data Validation dialog box is set to anything
except Stop, invalid data can be entered. Also, remember that data validation does not apply to
the calculated results of formulas. In other words, if the cell contains a formula, applying data validation
to that cell will have no effect.
The Data➜Data Tools➜Data Validation drop-down control contains an item named
Circle Invalid Data. When you click this item, circles appear around cells that contain
incorrect entries. If you correct an invalid entry, the circle disappears. To get rid of the
circles, choose Data➜Data Tools➜Data Validation➜Clear Validation Circles. In Figure
19-27, invalid entries are defined as values that are greater than 100.