Data validation is one of the best features in Excel. You can use it to create drop down lists, or limit what users can enter in a cell.

数据验证是Excel中最好的功能之一。 您可以使用它来创建下拉列表 ，或限制用户可以在单元格中输入的内容。

Unfortunately, data validation isn't perfect, or foolproof. Users can get around the limits, by pasting data into the cell, or by using the Clear All command in a data validation cell.

不幸的是，数据验证不是完美的或万无一失的。 用户可以通过将数据粘贴到单元格中或在数据验证单元格中使用“全部清除”命令来绕过限制。

Someone sent me a question this week, asking how to trap input errors, despite these data validation failings:

尽管这些数据验证失败，但有人在本周向我发送了一个问题，询问如何捕获输入错误：

• Hello! I was wondering, to you have any idea how to error trap a date input? I will enter dates on a specific column (complete dates such as 11/05/2010) and error trap if the input has the year of 2011 and not 2010. I know data validation does that, but only if the cell is manually inputted. If the input in the cell is pasted, it does not do that anymore.你好！ 我想知道，您对如何错误捕获日期输入有什么想法？ 如果输入的年份为2011年而不是2010年，我将在特定的列上输入日期(完整的日期，如11/05/2010)和错误陷阱。我知道数据验证会这样做，但前提是手动输入了单元格。 如果粘贴了单元格中的输入，它将不再这样做。

添加数据验证 (Add the Data Validation)

In this example, an order form has two cells for dates – an Order Date, and a Delivery Date. To ensure that a date for the current year is entered, you can use formulas in the data validation, to set a minimum and a maximum date.

在此示例中，订单中有两个日期单元格：“订单日期”和“交货日期”。 为确保输入当前年份的日期，您可以在数据验证中使用公式来设置最小和最大日期。

Start Date formula: =DATE(YEAR(TODAY()),1,1)

开始日期公式： = DATE(YEAR(TODAY())，1,1)

End Date formula: =DATE(YEAR(TODAY()),12,31)

结束日期公式： = DATE(YEAR(TODAY())，12,31)

检查日期 (Check the Date)

If you're concerned that users might paste values into the cell, or clear the data validation, you can add a formula check, to ensure that a valid date was entered. In the order form, a date check formula is entered in column G, which can be hidden.

如果您担心用户可能会将值粘贴到单元格中或清除数据验证，则可以添加公式检查以确保输入了有效日期。 在订单表中，日期检查公式输入到G列中，该公式可以隐藏。

The formula in cell G9 is:

G9单元格中的公式为：

=OR(C9="",YEAR(C9)=YEAR(TODAY()))

= OR(C9 =“”，YEAR(C9)= YEAR(TODAY()))

The formula is copied down to cell G10, and the result is FALSE, because the date in C10 is not in the current year.

该公式被复制到单元格G10中，结果为FALSE，因为C10中的日期不在当前年份。

冻结发票总额 (Block the Invoice Total)

In the Invoice total cell, the formula result is "Invalid Date", if either of the date check cells contains FALSE. If both dates are in the current year, the total sum is shown.

如果任一日期检查单元格包含FALSE，则在“发票总额”单元格中，公式结果为“无效日期”。 如果两个日期都在当年，则显示总计。

Here is the formula from the Invoice Total cell:

这是“发票总额”单元格中的公式：

=IF(COUNTIF(G9:G10,FALSE),"Invalid Date",SUM(E13:E17))

= IF(COUNTIF(G9：G10，FALSE)，“无效日期”，SUM(E13：E17))

其他解决方案 (Other Solutions)

Instead of a formula check, there are other ways to ensure that users enter valid data. For example, you could use Excel VBA to check specific cells before printing, and cancel the printing if the entries aren't valid.

除了公式检查外，还有其他方法可以确保用户输入有效数据。 例如，您可以使用Excel VBA在打印之前检查特定的单元格 ，如果条目无效则取消打印。

Have you used other methods to ensure that users don't ignore your data validation cells? ____________

您是否使用其他方法来确保用户不会忽略您的数据验证单元？ ____________