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Gets or sets the operator for the conditional format or data validation.
This property determines how the validation compares the cell value with Formula1 and, when applicable, Formula2.
ValidationOperator Operator { get; set; }
Property [Operator] As ValidationOperator
IRange range = worksheet.Range["A1"];
range.Validation.Add(ValidationType.Whole, ValidationAlertStyle.Stop, ValidationOperator.Between, 1, 10);
ValidationOperator validationOperator = range.Validation.Operator;