When a data validation is loaded from a file, EPPlus normalizes its formulas for ease of use. If the content of `ExcelFormula` is a valid literal value, such as `1`, it is exposed through `Formula.Value` instead. This gives you a typed value to work with rather than a formula string.

As an example, observe the following code:

```csharp
using(var package = new ExcelPackage(@"c:\temp\myWorkbook.xlsx"))
{
  var sheet = package.Workbook.Worksheets.Add("Example");
  var validation = sheet.DataValidations.AddIntegerValidation("A1");

  validation.Operator = ExcelDataValidationOperator.lessThan;
  validation.Formula.ExcelFormula = "1";
  SaveAndCleanup(package);
}
```

```vbnet
Using package As New ExcelPackage("c:\temp\myWorkbook.xlsx")
    Dim sheet = package.Workbook.Worksheets.Add("Example")
    Dim validation = sheet.DataValidations.AddIntegerValidation("A1")

    validation.Operator = ExcelDataValidationOperator.lessThan
    validation.Formula.ExcelFormula = "1"
    SaveAndCleanup(package)
End Using
```

When the workbook is loaded again, the validation looks like this:

```csharp
using(var package = new ExcelPackage(@"c:\temp\myWorkbook.xlsx"))
{
  var workSheet = package.Workbook.Worksheets[0];
  var validation = workSheet.DataValidations[0];

  var excelFormula = validation.Formula.Excelformula;
  var value = validation.Formula.Value;
}
```

```vbnet
Using package As New ExcelPackage("c:\temp\myWorkbook.xlsx")
    Dim workSheet = package.Workbook.Worksheets(0)
    Dim validation = workSheet.DataValidations(0)

    Dim excelFormula = validation.Formula.ExcelFormula
    Dim value = validation.Formula.Value
End Using
```

Since `"1"` is a valid value, EPPlus reads it as a value when the file is loaded, so you get:

- `excelFormula` = `null`
- `value` = `1`

For consistent results between the code that creates the validation and the code that reads it, we recommend assigning literal values to `Formula.Value`, and using `ExcelFormula` for cell addresses and other formulas.

### See also

- [Data validation](<https://epplussoftware.com/docs/worksheet-and-ranges/data-validation/index.md>)