EntityInstantFeedbackSource.DismissQueryable Event

Occurs when the EntityInstantFeedbackSource no longer needs the queryable source it used to retrieve objects from the data store.

Namespace: DevExpress.Data.Linq

Assembly: DevExpress.Data.v19.2.dll

Declaration

C#

public event EventHandler<GetQueryableEventArgs> DismissQueryable

VB.NET

Public Event DismissQueryable As EventHandler(Of GetQueryableEventArgs)

Event Data

The DismissQueryable event's data class is GetQueryableEventArgs. The following properties provide information specific to this event:

Property	Description
AreSourceRowsThreadSafe	Specifies whether elements retrieved by the LinqInstantFeedbackSource‘s queryable source are thread-safe.
KeyExpression	Gets or sets the name of the key property.
QueryableSource	Gets or sets the queryable data source.
Tag	Gets or sets an arbitrary object associated with a queryable source.

Remarks

You can access the object you have assigned to the GetQueryableEventArgs.Tag property in the EntityInstantFeedbackSource.GetQueryable event handler.

C#

public partial class Form1 : Form {
    private void Form1_Load(object sender, EventArgs e) {
        efInstantFeedbackSource1.KeyExpression = "EmployeeID";
        efInstantFeedbackSource1.GetQueryable += efInstantFeedbackSource1_GetQueryable;
        efInstantFeedbackSource1.DismissQueryable += efInstantFeedbackSource1_DismissQueryable;
        gridControl1.DataSource = efInstantFeedbackSource1;
    }
    void efInstantFeedbackSource1_GetQueryable(object sender, GetQueryableEventArgs e) {
        NorthwindEntities objectContext = new NorthwindEntities();
        e.QueryableSource = objectContext.Employees;
        e.Tag = objectContext;            
    }
    void efInstantFeedbackSource1_DismissQueryable(object sender, GetQueryableEventArgs e) {
        ((NorthwindEntities)e.Tag).Dispose();         
    }
}

VB.NET

Partial Public Class Form1
    Inherits Form
    Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs)
        efInstantFeedbackSource1.KeyExpression = "EmployeeID"
        AddHandler efInstantFeedbackSource1.GetQueryable, AddressOf efInstantFeedbackSource1_GetQueryable
        AddHandler efInstantFeedbackSource1.DismissQueryable, AddressOf efInstantFeedbackSource1_DismissQueryable
        gridControl1.DataSource = efInstantFeedbackSource1
    End Sub
    Private Sub efInstantFeedbackSource1_GetQueryable(ByVal sender As Object, ByVal e As GetQueryableEventArgs)
        Dim objectContext As New NorthwindEntities()
        e.QueryableSource = objectContext.Employees
        e.Tag = objectContext
    End Sub
    Private Sub efInstantFeedbackSource1_DismissQueryable(ByVal sender As Object, ByVal e As GetQueryableEventArgs)
        CType(e.Tag, NorthwindEntities).Dispose()
    End Sub
End Class