WinForms data sources such as ADO.NET and C1DataObjects contain provisions for detecting logical errors in data, by the data source itself or by the programmer, setting the RowError property or calling the SetColumnError method (SetFieldError in C1DataObjects). You can show logical row and column errors in C1Input using System.Windows.Form.ErrorProvider component.
To show logical column errors, use the ErrorProvider component with C1Input controls as you would use it with any other controls.
To show row error in C1DbNavigator control, set the ErrorProvider property to an ErrorProvider component. Then C1DbNavigator will display error icon with RowError ToolTip text when there is an error in current row.