Queryable Mode

• Jul 21, 2023
• 2 minutes to read

Mode Overview

The Queryable mode is the default mode in lookup List Views in ASP.NET Core Blazor applications. The collection source exposes an IQueryable<T> query shaped according to settings specified in a List View. In this mode, a List Editor does not load all objects immediately. The List Editor control extends the query to load only the objects visible in the control. After that, the editor iterates the query and loads objects from the database.

Note that the default data access mode for root and nested List Views in ASP.NET Core Blazor applications is Client.

Expected Behavior

• Only LookupPropertyEditor supports this mode.
• In this mode, List Views do not show custom persistent properties (IsCalculated = false) created in the Model Editor and the CustomizeTypesInfo method.
• This mode does not support the filter, sort, and group operations with the following properties:
  • Custom properties added at runtime.
  • Non-persistent properties that are not decorated with the PersistentAlias (XPO).
  • Non-persistent properties in EF Core.
• Queryable collection sources create a new collection from a query and use it instead of the original collection. As a result, custom logic implemented in an original collection’s getter and event handlers is not executed.
• This mode does not support legacy databases that use compound primary keys.
• Data-aware operations (such as grouping or sorting) are performed by the database server. This significantly increases the List View’s performance when you need to process a large number of objects. All properties are calculated when it is required (for example, if a property is visible in the List View or is used in the Appearance and Security rules).
• This mode does not support advanced syntaxes, such as:
  • The Single aggregate function
  • Free Joins (Query Non-Associated Data & Calculate Aggregations)
  • Upcasting (Combine Data from Base and Derived Classes)