What happens at runtime if a control is set to read-only?

When a control is set to read-only at runtime, it means that the user is unable to modify the value displayed in that control. This feature is important for scenarios where you want to present information to the user without allowing them to inadvertently change it. By ensuring the control is read-only, it helps prevent unintentional input errors and maintains data integrity.

In practical terms, a read-only control can still be displayed on the user interface; users will see the contained value, but any attempts to edit or input a new value will be ineffective. This is particularly useful in applications where certain fields need to be protected from user input, such as displaying calculated results or pre-filled values that should not be altered.

Overall, setting a control to read-only facilitates a clear distinction between data that is actively editable and information meant to be viewed only.