[]
Gets or sets whether the data validation input message is displayed whenever the user selects a cell in the data validation range.
Use this property to control whether the input message is shown for cells covered by this validation.
bool ShowInputMessage { get; set; }
Property ShowInputMessage As Boolean
IValidation validation = worksheet.Range["A1"].Validation;
validation.Add(ValidationType.List, ValidationAlertStyle.Stop, ValidationOperator.Between, "1,2,3", null);
validation.ShowInputMessage = true;
bool showInputMessage = validation.ShowInputMessage;