如何使用Apache POI在Excel文件中添加数据验证？

Question

I'm using Apache POI to create an excel file that contains dropdown lists. However, the dropdowns are still editable and the user will be able to type in values. I've seen in excel that I can display an error message when a user enters a value that is not on the list. Below is the part of the code where I set the constraints.

// Add dropdown for department column
    validationHelper = new XSSFDataValidationHelper(sheet);
    CellRangeAddressList addressList = new CellRangeAddressList(6, 10006, 2, 2);
// DVConstraint dvConstraint = DVConstraint.createExplicitListConstraint(departmentList);
    constraint = validationHelper.createExplicitListConstraint(departmentList);
    dataValidation = validationHelper.createValidation(constraint, addressList);
    dataValidation.setSuppressDropDownArrow(true);

    sheet.addValidationData(dataValidation);

I am able to display the list properly, however, it doesn't display an error message. Is it possible to do this? If so, how can I do it? Any help is much appreciated. Thanks.

Answer 1

You are missing the line

dataValidation.setShowErrorBox(true);

and you can customize the error box with

dataValidation.setErrorStyle(DataValidation.ErrorStyle.STOP);
dataValidation.createErrorBox("Title", "Message");

So together this is

var validationHelper = new XSSFDataValidationHelper(sheet);
var listConstraint = validationHelper.createExplicitListConstraint(departmentList);
var range = new CellRangeAddressList(6, 10006, 2, 2);

var dataValidation = validationHelper.createValidation(listConstraint, range);
dataValidation.setSuppressDropDownArrow(true);
dataValidation.setErrorStyle(DataValidation.ErrorStyle.STOP);
dataValidation.createErrorBox("Title", "Message");
dataValidation.setShowErrorBox(true);
sheet.addValidationData(dataValidation);