Why to add this validation feature to Combo Box Control?
The practical values of the combobox can be demonstrated from many aspects.
We need to check if it is equal to null or “” because different browsers act differently so its better to check for both the conditions.
The following function checks whether the texbox with id name1 is empty, if empty it displays a message and highlights that textbox with red color.
An HTML combobox shows a dropdown list of items from which one item is selected.
The image attached below shows the result of above combobox validating programming examples.
Another quick post on validating a form using the String Validator, Number Validator, Zip Code Validator and Validator classes.
Thankfully Win Forms has built in mechanisms to help facilitate data validation.
Each control has the following events and properties that are used to validate a form. Validation on a control is triggered when the control loses focus. Cancel Event Args] object as a parameter to the event block, which you can access this by using the in the Validating event, all events that would usually occur after the Validating event are suppressed.