Validating two user controls
The width of the displayed drop-down list matches the value that you entered into the form control's parameter (200).
If you do not choose any color, the validation error message defined in the code of the form control appears.
You can use the same basic approach to create any type of custom form control.
Note: This example implements the custom form control as a Web user control (file) within the Kentico web project.
Unlike the traditional user controls, field templates do not require registration.
Instead, a simple placed on a web page automatically loads and configures an appropriate field template based the column name and metadata.
Although they are a great mechanism for reusing presentation and validation logic, user controls require a certain amount of plumbing before they can be used on a web page.
At the very minimum, user controls must be registered, and because even the simplest controls need to provide slightly varying functionality in different contexts, they also usually have one or more properties that need to be configured.
The value of the property is used in the Ensure Items() method to set the width of the internal drop-down list.Your feedback and constructive contributions are welcome.