Architecture for validating input. A control is associated with a data source via a Binding. The control is arranged to receive user input with which to update the data source. In addition, zero or more validation rules are associated with the Binding and executed to validate the input. If the user input is invalid or an exception occurs while converting the input or updating the data source, a validation error object may be created and attached to the control. To provide feedback to the user, a control defines additional user interface elements to adorn the control and display the created validation error information to the user.