EntityInstantFeedbackSource.GetQueryable Event
Occurs when the EntityInstantFeedbackSource needs a queryable source, to retrieve objects from the data store.
Namespace: DevExpress.Data.Linq
Assembly: DevExpress.Data.v18.2.dll
Declaration
Event Data
The GetQueryable 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
Handle this event, to supply a queryable source connected to the required data service. The GetQueryableEventArgs class exposes the GetQueryableEventArgs.Tag property, which you can use to specify an arbitrary object. This object will be passed along with the GetQueryableEventArgs.QueryableSource property to the EntityInstantFeedbackSource.DismissQueryable event handler.
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();
}
}
See Also