Working in an Excel spreadsheet can be somewhat like the Wild West – unless other provisions are made, users can enter any value in any cell. One way you can restrict users to a predefined set of values is by way of Excel's Data Validation feature. I'll explain how you can create in-cell drop-down lists, along with how to "future proof" the Data Validation list so that the feature won't require maintenance if you add additional items in the future. This technique also resolves an annoying problem in Excel 2007 where data validation lists cannot be placed on other worksheets.
Before we look at Data Validation, let's first establish our list. Let's say we want the user to choose a type of fruit. On the second worksheet of a blank workbook, create a list, such as shown in Figure 1. Once you do so, make the list into a Table in Excel 2007 and later, or a List in Excel 2003 and earlier. After you click on any cell within your list:
- Excel 2007 and later – Choose Insert and then Table. Make sure that My Table Has Headers is selected and then click OK.
- Excel:Mac 2011 – On the Tables tab of the ribbon, click the arrow next to the New command and then choose Insert Table with Headers.
- Excel 2003 and earlier – Choose Data, List, and then Create List.