WcfInstantFeedbackSource Class

The data source for the GridControl and SearchLookUpEdit controls that binds these controls to a WCF Data Service in Instant Feedback Mode.

Namespace : DevExpress.Data.WcfLinq

Assembly : DevExpress.Data.v25.2.dll

NuGet Package : DevExpress.Data

Declaration

C#
VB.NET

csharp

[ToolboxBitmap(typeof(ResFinder), "Bitmaps256.WcfInstantFeedbackSource.bmp")]
public class WcfInstantFeedbackSource :
    Component,
    IListSource,
    IDXCloneable,
    IOdata

<ToolboxBitmap(GetType(ResFinder), "Bitmaps256.WcfInstantFeedbackSource.bmp")>
Public Class WcfInstantFeedbackSource
    Inherits Component
    Implements IListSource,
               IDXCloneable,
               IOdata

Remarks

Instant Feedback binding mode is an improvement over regular server mode. In server mode, the Grid Control loads data in small portions and delegates all data operations (sorting, grouping, filtering and calculating summaries) to the data server. This is the key to the server mode’s high efficiency when working with large volumes of data. The only drawback to using server mode involves data operations when the connection to the server is slow. In this instance, the bound control freezes until the data server completes operations and retrieves results. With Instant Feedback binding mode, data operations are performed asynchronously in a background thread, and both the bound control and the application remain highly responsive. Currently, this mode is supported by the GridControl and SearchLookUpEdit controls.

For additional information on Instant Feedback mode, refer to the Large Data Sources: Server and Instant Feedback Modes section.

Note

The WcfInstantFeedbackSource is a read-only data source.

C#
VB.NET

csharp

public partial class Form1 : Form {
    private void Form1_Load(object sender, EventArgs e) {
        wcfInstantFeedbackSource1.KeyExpression = "CustomerID";
        wcfInstantFeedbackSource1.GetSource += wcfInstantFeedbackSource1_GetSource;
        gridControl1.DataSource = wcfInstantFeedbackSource1;
    }
    void wcfInstantFeedbackSource1_GetSource(object sender, GetSourceEventArgs e) {
        // DataServiceContext myDataServiceContext = ...
        e.Query = myDataServiceContext.Customers;
    }
}

Partial Public Class Form1
    Inherits Form
    Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs)
        wcfInstantFeedbackSource1.KeyExpression = "CustomerID"
        AddHandler wcfInstantFeedbackSource1.GetSource, AddressOf wcfInstantFeedbackSource1_GetSource
        gridControl1.DataSource = wcfInstantFeedbackSource1
    End Sub
    Private Sub wcfInstantFeedbackSource1_GetSource(ByVal sender As Object, ByVal e As GetSourceEventArgs)
        ' DataServiceContext myDataServiceContext = ...
        e.Query = myDataServiceContext.Customers
    End Sub
End Class

Inheritance

Object MarshalByRefObject Component WcfInstantFeedbackSource