Add Item to MultiSelect

Generally, a multiselect or combo box widgets allows the user to select a predefined options and if you want to allow them to add more options, a more robust data editing component should be used (such as a grid or listview).

Nevertheless, it is possible to hack the component to:

• show an "Add" button if the data does not contain a match for the current input
• update the data source, current Data and Value through a few hacks in that button click and the OnRead handler

This example showcases one way you could do this. The component with the multiselect is in the Shared folder, and comments in the code offer more insights into the implementation.