true if the editor's value has been validated; false if the editor's value is invalid.
The DoValidate method is automatically called by the editor or its container control, each time the editor's value should be validated. This occurs when an end-user accepts the edit value (for example, when the editor is about to lose focus).
Use the DoValidate method to manually force the validation. If the editor's BaseEdit.CausesValidation property is set to true, the editor fires the BaseEdit.Validate event, allowing you to manually validate its value.