public class XPQuery<T> :
    XPQueryBase,
    IOrderedQueryable<T>,
    IQueryable<T>,
    IEnumerable<T>,
    IEnumerable,
    IQueryable,
    IOrderedQueryable,
    IQueryProvider

Public Class XPQuery(Of T)
    Inherits XPQueryBase
    Implements IOrderedQueryable(Of T),
               IQueryable(Of T),
               IEnumerable(Of T),
               IEnumerable,
               IQueryable,
               IOrderedQueryable,
               IQueryProvider

Type Parameters

Name	Description
T

Remarks

To execute LINQ queries for persistent objects, perform the following steps:

Create the XPQuery<T> instance of the required type.
Write the required LINQ queries for the created XPQuery<T> instance.

The following code snippet illustrates this. It prints the last names of all the customers named "John":

C#
VB.NET


using DevExpress.Xpo;

//...

Session MainSession = new Session();
XPQuery<Customer> customersQuery = new XPQuery<Customer>(MainSession);

var customers = from c in customersQuery
                where c.Name == "John"
                select c;

foreach (Customer customer in customers)
    Console.WriteLine(customer.LastName);


Imports DevExpress.Xpo

'...

Dim MainSession As New Session()
Dim customersQuery As XPQuery(Of Customer) = New XPQuery(Of Customer)(MainSession)

Dim customers = from c in customersQuery where c.Name = "John" select c

For Each customer As Customer In customers
    Console.WriteLine(customer.LastName)
Next customer

For more examples on using the XPQuery<T> class, refer to the LINQ to XPO knowledge base article.

XPO LINQ expressions are processed on the database server side and only the requested objects are loaded into the application.

Object

XPQueryBase

XPQuery<T>

Implements

DevExpress.Xpo.Helpers.IPersistentValueExtractor

IOrderedQueryable<T>

IQueryable<T>

IEnumerable<T>

Extension Methods

XPQueryExtensions.EnumerateAsync<T>(IQueryable<T>, XPQueryExtensions.AsyncEnumerateCallback<T>)

XPQueryExtensions.EnumerateAsync<T>(IQueryable<T>, XPQueryExtensions.AsyncEnumerateCallback)

XPQueryExtensions.EnumerateAsync<T>(IQueryable<T>, CancellationToken)

XPQueryExtensions.CachedExpression<TSource, TResult>(IQueryable<TSource>, Func<IQueryable<TSource>, TResult>)

XPQueryExtensions.CachedExpression<TSource, TArg1, TResult>(IQueryable<TSource>, Func<IQueryable<TSource>, TArg1, TResult>, TArg1)

XPQueryExtensions.CachedExpression<TSource, TArg1, TArg2, TResult>(IQueryable<TSource>, Func<IQueryable<TSource>, TArg1, TArg2, TResult>, TArg1, TArg2)

XPQueryExtensions.CachedExpression<TSource, TArg1, TArg2, TArg3, TResult>(IQueryable<TSource>, Func<IQueryable<TSource>, TArg1, TArg2, TArg3, TResult>, TArg1, TArg2, TArg3)

XPQueryExtensions.CachedExpression<TSource, TArg1, TArg2, TArg3, TArg4, TResult>(IQueryable<TSource>, Func<IQueryable<TSource>, TArg1, TArg2, TArg3, TArg4, TResult>, TArg1, TArg2, TArg3, TArg4)

XPQueryExtensions.CachedExpression<TSource, TArg1, TArg2, TArg3, TArg4, TArg5, TResult>(IQueryable<TSource>, Func<IQueryable<TSource>, TArg1, TArg2, TArg3, TArg4, TArg5, TResult>, TArg1, TArg2, TArg3, TArg4, TArg5)

XPQueryExtensions.ToListAsync<T>(IQueryable<T>, CancellationToken)

XPQueryExtensions.ToArrayAsync<T>(IQueryable<T>, CancellationToken)

XPQueryExtensions.ToDictionaryAsync<T, TKey>(IQueryable<T>, Func<T, TKey>, CancellationToken)

XPQueryExtensions.ToDictionaryAsync<T, TKey, TElement>(IQueryable<T>, Func<T, TKey>, Func<T, TElement>, IEqualityComparer<TKey>, CancellationToken)

XPQueryExtensions.ToDictionaryAsync<T, TKey, TElement>(IQueryable<T>, Func<T, TKey>, Func<T, TElement>, CancellationToken)

XPQueryExtensions.ToDictionaryAsync<T, TKey>(IQueryable<T>, Func<T, TKey>, IEqualityComparer<TKey>, CancellationToken)

XPQueryExtensions.ToLookupAsync<T, TKey>(IQueryable<T>, Func<T, TKey>, CancellationToken)

XPQueryExtensions.ToLookupAsync<T, TKey, TElement>(IQueryable<T>, Func<T, TKey>, Func<T, TElement>, CancellationToken)

XPQueryExtensions.ToLookupAsync<T, TKey, TElement>(IQueryable<T>, Func<T, TKey>, Func<T, TElement>, IEqualityComparer<TKey>, CancellationToken)

XPQueryExtensions.ToLookupAsync<T, TKey>(IQueryable<T>, Func<T, TKey>, IEqualityComparer<TKey>, CancellationToken)

XPQueryExtensions.ElementAtAsync<T>(IQueryable<T>, Int32, CancellationToken)

XPQueryExtensions.ElementAtOrDefaultAsync<T>(IQueryable<T>, Int32, CancellationToken)

XPQueryExtensions.CountAsync<T>(IQueryable<T>, CancellationToken)

XPQueryExtensions.CountAsync<T>(IQueryable<T>, Expression<Func<T, Boolean>>, CancellationToken)

XPQueryExtensions.LongCountAsync<T>(IQueryable<T>, CancellationToken)

XPQueryExtensions.LongCountAsync<T>(IQueryable<T>, Expression<Func<T, Boolean>>, CancellationToken)

XPQueryExtensions.ContainsAsync<T>(IQueryable<T>, T, CancellationToken)

XPQueryExtensions.AnyAsync<T>(IQueryable<T>, CancellationToken)

XPQueryExtensions.AnyAsync<T>(IQueryable<T>, Expression<Func<T, Boolean>>, CancellationToken)

XPQueryExtensions.AllAsync<T>(IQueryable<T>, Expression<Func<T, Boolean>>, CancellationToken)

XPQueryExtensions.FirstAsync<T>(IQueryable<T>, CancellationToken)

XPQueryExtensions.FirstAsync<T>(IQueryable<T>, Expression<Func<T, Boolean>>, CancellationToken)

XPQueryExtensions.FirstOrDefaultAsync<T>(IQueryable<T>, CancellationToken)

XPQueryExtensions.FirstOrDefaultAsync<T>(IQueryable<T>, Expression<Func<T, Boolean>>, CancellationToken)

XPQueryExtensions.LastAsync<T>(IQueryable<T>, CancellationToken)

XPQueryExtensions.LastAsync<T>(IQueryable<T>, Expression<Func<T, Boolean>>, CancellationToken)

XPQueryExtensions.LastOrDefaultAsync<T>(IQueryable<T>, CancellationToken)

XPQueryExtensions.LastOrDefaultAsync<T>(IQueryable<T>, Expression<Func<T, Boolean>>, CancellationToken)

XPQueryExtensions.SingleAsync<T>(IQueryable<T>, CancellationToken)

XPQueryExtensions.SingleAsync<T>(IQueryable<T>, Expression<Func<T, Boolean>>, CancellationToken)

XPQueryExtensions.SingleOrDefaultAsync<T>(IQueryable<T>, CancellationToken)

XPQueryExtensions.SingleOrDefaultAsync<T>(IQueryable<T>, Expression<Func<T, Boolean>>, CancellationToken)

XPQueryExtensions.MinAsync<T>(IQueryable<T>, CancellationToken)

XPQueryExtensions.MinAsync<T, TResult>(IQueryable<T>, Expression<Func<T, TResult>>, CancellationToken)

XPQueryExtensions.MaxAsync<T>(IQueryable<T>, CancellationToken)

XPQueryExtensions.MaxAsync<T, TResult>(IQueryable<T>, Expression<Func<T, TResult>>, CancellationToken)

XPQueryExtensions.SumAsync<T>(IQueryable<T>, Expression<Func<T, Int32>>, CancellationToken)

XPQueryExtensions.SumAsync<T>(IQueryable<T>, Expression<Func<T, Nullable<Int32>>>, CancellationToken)

XPQueryExtensions.SumAsync<T>(IQueryable<T>, Expression<Func<T, Int64>>, CancellationToken)

XPQueryExtensions.SumAsync<T>(IQueryable<T>, Expression<Func<T, Nullable<Int64>>>, CancellationToken)

XPQueryExtensions.SumAsync<T>(IQueryable<T>, Expression<Func<T, Decimal>>, CancellationToken)

XPQueryExtensions.SumAsync<T>(IQueryable<T>, Expression<Func<T, Nullable<Decimal>>>, CancellationToken)

XPQueryExtensions.SumAsync<T>(IQueryable<T>, Expression<Func<T, Single>>, CancellationToken)

XPQueryExtensions.SumAsync<T>(IQueryable<T>, Expression<Func<T, Nullable<Single>>>, CancellationToken)

XPQueryExtensions.SumAsync<T>(IQueryable<T>, Expression<Func<T, Double>>, CancellationToken)

XPQueryExtensions.SumAsync<T>(IQueryable<T>, Expression<Func<T, Nullable<Double>>>, CancellationToken)

XPQueryExtensions.AverageAsync<T>(IQueryable<T>, Expression<Func<T, Int32>>, CancellationToken)

XPQueryExtensions.AverageAsync<T>(IQueryable<T>, Expression<Func<T, Int64>>, CancellationToken)

XPQueryExtensions.AverageAsync<T>(IQueryable<T>, Expression<Func<T, Decimal>>, CancellationToken)

XPQueryExtensions.AverageAsync<T>(IQueryable<T>, Expression<Func<T, Single>>, CancellationToken)

XPQueryExtensions.AverageAsync<T>(IQueryable<T>, Expression<Func<T, Double>>, CancellationToken)

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General Information

.NET Subscription

Common Tools

Desktop

Controls

Tools

Web

Controls and Extensions

Tools

Enterprise and Analytic Tools

Code / Debug / Refactor

Frameworks and Libraries

Mobile

XPQuery<T> Class

Declaration

Type Parameters

Remarks

Inheritance

Implements

Extension Methods