Session.PreFetch<T>(IEnumerable<T>, String[]) Method

Enforces loading data for associated collections and delayed properties.

Namespace: DevExpress.Xpo

Assembly: DevExpress.Xpo.v23.2.dll

NuGet Packages: DevExpress.Win.PivotGrid, DevExpress.Win.TreeMap, DevExpress.Xpo

NuGet Package: DevExpress.Xpo

Declaration

C#

public void PreFetch<T>(
    IEnumerable<T> objects,
    params string[] propertyPaths
)
    where T : class

VB.NET

Public Sub PreFetch(Of T As Class)(
    objects As IEnumerable(Of T),
    ParamArray propertyPaths As String()
)

Parameters

Name	Type	Description
objects	IEnumerable<T>	An IEnumerable list of parent objects.
propertyPaths	String[]	An array of strings that are the collection property and delayed property names, or property paths (e.g, “ChildCollection.AnotherChildCollection”).

Type Parameters

Name	Description
T	The type of elements in the list of parent objects.

Remarks

By default, data is loaded automatically when you access a nested collection or delayed property for the first time. When the PreFetch<T> method is called, all data for the specified collections and delayed properties is loaded at once. No additional SQL queries for this data will be performed later.

C#

using DevExpress.Xpo;
using DevExpress.Xpo.Metadata;
// ...
XPCollection<Person> people = new XPCollection<Person>(session);
session.PreFetch<Person>(people, nameof(PhoneNumbers));

VB.NET

Imports DevExpress.Xpo
Imports DevExpress.Xpo.Metadata
' ...
Private people As New XPCollection(Of Person)(session)
session.PreFetch(Of Person)(people, NameOf(PhoneNumbers))

If you specify a property path, the PreFetch method loads every delayed property that exists in the specified path.