List View Data Access Modes

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Choose Data Access Mode

Client is the default mode in WinForms and ASP.NET Web Forms applications. The Server, ServerView, DataView, InstantFeedback, and InstantFeedbackView modes optimize how a List View loads and processes data in different scenarios. In ASP.NET Core Blazor applications, the default mode for root and lookup List Views is Queryable. The default mode for nested List Views in Blazor application is Client.

  • If you have a large number of objects to display in a List View, use Server or InstantFeedback mode in WinForms and ASP.NET Web Forms applications, and Queryable mode in ASP.NET Core Blazor applications.
  • If objects you want to display in a List View have a complicated structure (for example, many reference properties), use DataView mode.
  • If you have a large number of objects to display in a List View and these objects have a complicated structure, use ServerView or InstantFeedbackView mode.

The following table explains the different modes:

Criteria

Client

Queryable

Server

ServerView

DataView

InstantFeedback

InstantFeedbackView

Supported Platforms

WinForms
Web Forms
Blazor

ASP.NET Core Blazor

WinForms
Web Forms

WinForms

WinForms
Web Forms

WinForms

WinForms

Supported ORM

EF 6, XPO

EF Core, XPO

EF 6, XPO

XPO

EF 6, XPO

EF 6, XPO

XPO

Supported ListEditors

all

GridListEditor

GridListEditor ASPxGridListEditor

GridListEditor

GridListEditor SchedulerListEditor PivotGridListEditor ASPxGridListEditor ASPxSchedulerListEditor ASPxPivotGridListEditor

GridListEditor

GridListEditor

Processed object

original object

original object

original object

ObjectRecord

XafDataViewRecord

ObjectRecord

ObjectRecord

Columns available for processing

displayed columns and columns from the Model

displayed columns

displayed columns and columns from the Model

displayed columns and displayable properties from an original collection

displayed columns

displayed columns and displayable properties from an original collection

displayed columns and displayable properties from an original collection

Initially loaded objects

all

displayed

displayed

displayed

all

displayed

displayed

Asynchronous loading

not supported

not supported

not supported

not supported

not supported

supported

supported

Non-persistent properties

supported

supported with limitations

supported with limitations

supported with limitations

supported with limitations

supported with limitations

supported with limitations

Once you select the mode, navigate to its topic for more information.

The following video explains the best ways to access and manipulate data in XAF, and how to build high-performance apps.

Non-Persistent Properties Support Limitations

Non-persistent properties are properties that return a value calculated at runtime or store a temporary value in memory. The following list describes their limitations in specific data access modes:

  • In ServerView, DataView, and InstantFeedbackView modes, List Editors do not display non-persistent property values.
  • In Server and Queryable modes, List Editors display non-persistent properties but do not allow you to filter, sort, or group them.

To use non-persistent properties in these modes, decorate them with the PersistentAlias (XPO) or Calculated (EF) attribute. For more information, refer to the following KB article: Is it possible to avoid the “Cannot query a data store using criterion (…)” error and be able to filter, sort and group by non-persistent fields in server mode?.

Specify Data Access Mode

To specify a List View’s data access mode, invoke the Model Editor, navigate to the Views | <ListView> node, and set the IModelListView.DataAccessMode property to one of CollectionSourceDataAccessMode‘s values.

DataAccessMode

DataAccessMode‘s combo box displays only modes that are compatible with the selected List Editor (a node’s EditorType property). If you use a custom List Editor, specify its supported modes in the static DataAccessModeHelper.RegisterEditorSupportedModes method. Call this method from code executed at design time before the Model Editor is loaded (for example, from a Module’s constructor). Pass the List Editor’s type and a list of supported modes to this method. Otherwise, the Model Editor shows all modes for this List Editor.

using System.Collections.Generic;
using DevExpress.ExpressApp;
using DevExpress.ExpressApp.Utils;
// ...
public sealed partial class MySolutionWinModule : ModuleBase {
    public MySolutionWinModule() {
        // ...
        DataAccessModeHelper.RegisterEditorSupportedModes(typeof(CustomListEditor), 
        new List<CollectionSourceDataAccessMode> { CollectionSourceDataAccessMode.Client, CollectionSourceDataAccessMode.Server });
    }
    // ...
}

To change data access mode for all List Views in an application (except for autogenerated nested List Views), invoke the Model Editor, navigate to the Options node, and specify its DataAccessMode property. To specify the data access mode for nested List Views, set the IModelListView.DataAccessMode property for each nested List View node as described above.

Note that you can use CollectionSource constructors with the dataAccessMode parameter when you create a List View’s collection source in code.

See Also