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Server Mode and Instant Feedback Mode

  • 4 minutes to read

The DevExpress WPF suite includes multiple binding mechanisms that allow you to work with large data sources. The following article describes Server Mode and Instant Feedback Mode capabilities.

Run Demo: Entity Framework Server Mode and Instant Feedback Mode

Server Mode

We recommend that you use Server Mode if you bind the GridControl to a large data collection. In this mode, the GridControl loads data in batches on request. The control displays loaded data and fetches a new batch if the user scrolls to the last loaded record.

In this mode, the GridControl performs all data shaping operations on the server side.

Server Mode

To activate Server Mode, bind the GridControl to one of the collections listed in the Data Access Technologies section.

In Server Mode, performance depends on the batch size, the source collection type, and the network connection. If visible UI lags appear, you can use Instant Feedback Mode.

Instant Feedback Mode

Instant Feedback Mode is an asynchronous Server Mode. In this mode, the UI remains active while the GridControl loads data. The user can scroll, sort, group, and filter records. The control cancels the data request and creates a new request depending on the user’s actions.

Instant Feedback Mode

To activate Instant Feedback Mode, bind the GridControl to one of the collections listed in the Data Access Technologies section.

In Instant Feedback Mode, the GridControl operates with wrappers for objects, but not real objects to avoid thread-safe issues. Use the Data.[FieldName] binding path in cell styles/templates and the DataContext.[FieldName] binding path in row styles/templates to access the data item’s properties (replace [FieldName] with a column’s FieldName):

<Style TargetType="dxg:LightweightCellEditor">
    <Setter Property="ToolTip" Value="{Binding Path=Data.YourFieldName}" />

You can display animation that informs the user while the GridControl loads data. To do this, specify the following properties:

Property Description
DataViewBase.RowAnimationKind Specifies the animation that is displayed while the GridControl asynchronously retrieves data from the source.
DataViewBase.WaitIndicatorType Specifies the indicator that is displayed while the GridControl asynchronously loads data.
DataViewBase.WaitIndicatorStyle Specifies the template that defines the wait indicator’s appearance.

The GridControl raises the following events when it loads data asynchronously:

The IsAsyncOperationInProgress property shows the load operation status.

Data Access Technologies

The GridControl allows you to work with multiple data access technologies in Server Mode and Instant Feedback Mode:

Data Access Technology Instant Feedback UI Data Source Server Mode Data Source
Entity Framework 4+ EntityInstantFeedbackSource EntityServerModeSource
eXpress Persistent Objects XPInstantFeedbackSource XPServerCollectionSource
OData v4 ODataInstantFeedbackSource ODataServerModeSource
WCF Data Services WcfInstantFeedbackSource WcfServerModeSource
LINQ to SQL LinqInstantFeedbackSource LinqServerModeSource
Parallel LINQ to Objects PLinqInstantFeedbackSource PLinqServerModeSource

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Refer to the following topic for information on the limitations of Server Mode: Server Mode Limitations.


View Example: Bind the WPF Data Grid to Data

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