Large lookup lists should not load every record when the page opens. A Telerik RadComboBox can load a small initial batch, filter as the user types, and retrieve additional rows only when the user scrolls.
This example uses the Architect selector on the CRM Project card. It returns 25 Architects at a time and supports both type-ahead filtering and virtual scrolling.
How It Works
The solution has three parts:
- A SQL stored procedure accepts:
- The text entered by the user.
- The number of records already loaded.
- The
RadComboBox requests additional results as the user types or scrolls.
- The
ItemsRequested event passes Telerik’s e.NumberOfItems value to SQL as the offset.
The result is a lazy-loaded lookup:
- Initial open: first 25 active Architects.
- User types
design: first 25 Architect names containing design.
- User scrolls: next 25 matching records are loaded.
- The dropdown stops requesting more records when SQL returns fewer than 25 rows.