Thank you for your interest in RadAutoComplete for Xamarin.
I will go straight to your questions:
1 and 2: RadAutocomplete could be bound to a list of business objects via a ViewModel, the actual data could be retrieved in various ways including SQLite database. I have created a sample project to demonstrate how you could populate the control after getting the items asynchronously - the example is based on the following tutorial and sample app: Xamarin.Forms Local Databases.
3. In the attached example I've used a class named CategoryItem with a unique ID marked with PrimaryKey and AutoIncrement attributes like this:
4. This seems as a straightforward solution, however it's more of application logic and as I am not aware of the exact setup and the requirements you have, I'd prefer not giving recommendations on this.
Let me know if I can assist with anything else.
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