Add data validation to Excel ranges

Article
03/22/2022

The Excel JavaScript Library provides APIs to enable your add-in to add automatic data validation to tables, columns, rows, and other ranges in a workbook. To understand the concepts and the terminology of data validation, please see the following articles about how users add data validation through the Excel UI.

Programmatic control of data validation

The Range.dataValidation property, which takes a DataValidation object, is the entry point for programmatic control of data validation in Excel. There are five properties to the DataValidation object:

rule — Defines what constitutes valid data for the range. See DataValidationRule.
errorAlert — Specifies whether an error pops up if the user enters invalid data, and defines the alert text, title, and style; for example, information, warning, and stop. See DataValidationErrorAlert.
prompt — Specifies whether a prompt appears when the user hovers over the range and defines the prompt message. See DataValidationPrompt.
ignoreBlanks — Specifies whether the data validation rule applies to blank cells in the range. Defaults to true.
type — A read-only identification of the validation type, such as WholeNumber, Date, TextLength, etc. It is set indirectly when you set the rule property.

Note

Data validation added programmatically behaves just like manually added data validation. In particular, note that data validation is triggered only if the user directly enters a value into a cell or copies and pastes a cell from elsewhere in the workbook and chooses the Values paste option. If the user copies a cell and does a plain paste into a range with data validation, validation is not triggered.

Creating validation rules

To add data validation to a range, your code must set the rule property of the DataValidation object in Range.dataValidation. This takes a DataValidationRule object which has seven optional properties. No more than one of these properties may be present in any DataValidationRule object. The property that you include determines the type of validation.

Basic and DateTime validation rule types

The first three DataValidationRule properties (i.e., validation rule types) take a BasicDataValidation object as their value.

wholeNumber — Requires a whole number in addition to any other validation specified by the BasicDataValidation object.
decimal — Requires a decimal number in addition to any other validation specified by the BasicDataValidation object.
textLength — Applies the validation details in the BasicDataValidation object to the length of the cell's value.

Here is an example of creating a validation rule. Note the following about this code.

The operator is the binary operator greaterThan. Whenever you use a binary operator, the value that the user tries to enter in the cell is the left-hand operand and the value specified in formula1 is the right-hand operand. So this rule says that only whole numbers that are greater than 0 are valid.
The formula1 is a hard-coded number. If you don't know at coding time what the value should be, you can also use an Excel formula (as a string) for the value. For example, "=A3" and "=SUM(A4,B5)" could also be values of formula1.

await Excel.run(async (context) => {
    let sheet = context.workbook.worksheets.getActiveWorksheet();
    let range = sheet.getRange("B2:C5");

    range.dataValidation.rule = {
            wholeNumber: {
                formula1: 0,
                operator: Excel.DataValidationOperator.greaterThan
            }
        };

    await context.sync();
});

See BasicDataValidation for a list of the other binary operators.

There are also two ternary operators: between and notBetween. To use these, you must specify the optional formula2 property. The formula1 and formula2 values are the bounding operands. The value that the user tries to enter in the cell is the third (evaluated) operand. The following is an example of using the "Between" operator.

await Excel.run(async (context) => {
    let sheet = context.workbook.worksheets.getActiveWorksheet();
    let range = sheet.getRange("B2:C5");

    range.dataValidation.rule = {
            decimal: {
                formula1: 0,
                formula2: 100,
              operator: Excel.DataValidationOperator.between
            }
        };

    await context.sync();
});

The next two rule properties take a DateTimeDataValidation object as their value.

date
time

The DateTimeDataValidation object is structured similarly to the BasicDataValidation: it has the properties formula1, formula2, and operator, and is used in the same way. The difference is that you cannot use a number in the formula properties, but you can enter a ISO 8606 datetime string (or an Excel formula). The following is an example that defines valid values as dates in the first week of April, 2022.

await Excel.run(async (context) => {
    let sheet = context.workbook.worksheets.getActiveWorksheet();
    let range = sheet.getRange("B2:C5");

    range.dataValidation.rule = {
            date: {
                formula1: "2022-04-01",
                formula2: "2022-04-08",
                operator: Excel.DataValidationOperator.between
            }
        };

    await context.sync();
});

List validation rule type

Use the list property in the DataValidationRule object to specify that the only valid values are those from a finite list. The following is an example. Note the following about this code.

It assumes that there is a worksheet named "Names" and that the values in the range "A1:A3" are names.
The source property specifies the list of valid values. The string argument refers to a range containing the names. You can also assign a comma-delimited list; for example: "Sue, Ricky, Liz".
The inCellDropDown property specifies whether a drop-down control will appear in the cell when the user selects it. If set to true, then the drop-down appears with the list of values from the source.

await Excel.run(async (context) => {
    let sheet = context.workbook.worksheets.getActiveWorksheet();
    let range = sheet.getRange("B2:C5");   
    let nameSourceRange = context.workbook.worksheets.getItem("Names").getRange("A1:A3");

    range.dataValidation.rule = {
        list: {
            inCellDropDown: true,
            source: "=Names!$A$1:$A$3"
        }
    };

    await context.sync();
})

Custom validation rule type

Use the custom property in the DataValidationRule object to specify a custom validation formula. The following is an example. Note the following about this code.

It assumes there is a two-column table with columns Athlete Name and Comments in the A and B columns of the worksheet.
To reduce verbosity in the Comments column, it makes data that includes the athlete's name invalid.
SEARCH(A2,B2) returns the starting position, in string in B2, of the string in A2. If A2 is not contained in B2, it does not return a number. ISNUMBER() returns a boolean. So the formula property says that valid data for the Comment column is data that does not include the string in the Athlete Name column.

await Excel.run(async (context) => {
    let sheet = context.workbook.worksheets.getActiveWorksheet();
    let commentsRange = sheet.tables.getItem("AthletesTable").columns.getItem("Comments").getDataBodyRange();

    commentsRange.dataValidation.rule = {
            custom: {
                formula: "=NOT(ISNUMBER(SEARCH(A2,B2)))"
            }
        };

    await context.sync();
});

Create validation error alerts

You can a create custom error alert that appears when a user tries to enter invalid data in a cell. The following is a simple example. Note the following about this code.

The style property determines whether the user gets an informational alert, a warning, or a "stop" alert. Only stop actually prevents the user from adding invalid data. The pop-ups for warning and information have options that allow the user enter the invalid data anyway.
The showAlert property defaults to true. This means that Excel will pop-up a generic alert (of type stop) unless you create a custom alert which either sets showAlert to false or sets a custom message, title, and style. This code sets a custom message and title.

await Excel.run(async (context) => {
    let sheet = context.workbook.worksheets.getActiveWorksheet();
    let range = sheet.getRange("B2:C5");

    range.dataValidation.errorAlert = {
            message: "Sorry, only positive whole numbers are allowed",
            showAlert: true, // The default is 'true'.
              style: Excel.DataValidationAlertStyle.stop,
            title: "Negative or Decimal Number Entered"
        };

    // Set range.dataValidation.rule and optionally .prompt here.

    await context.sync();
});

For more information, see DataValidationErrorAlert.

Create validation prompts

You can create an instructional prompt that appears when a user hovers over, or selects, a cell to which data validation has been applied. The following is an example.

await Excel.run(async (context) => {
    let sheet = context.workbook.worksheets.getActiveWorksheet();
    let range = sheet.getRange("B2:C5");

    range.dataValidation.prompt = {
            message: "Please enter a positive whole number.",
            showPrompt: true, // The default is 'false'.
            title: "Positive Whole Numbers Only."
        };

    // Set range.dataValidation.rule and optionally .errorAlert here.

    await context.sync();
});

For more information, see DataValidationPrompt.

Remove data validation from a range

To remove data validation from a range, call the Range.dataValidation.clear() method.

myrange.dataValidation.clear()

It isn't necessary that the range you clear is exactly the same range as a range on which you added data validation. If it isn't, only the overlapping cells, if any, of the two ranges are cleared.