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.NET Development
.NET Framework 3.5
CompiledQuery Class
.NET Framework Class Library
CompiledQuery Class

Updated: November 2007

Represents a cached LINQ to Entities query.

Namespace:  System.Data.Objects
Assembly:  System.Data.Entity (in System.Data.Entity.dll)

Visual Basic (Declaration)
Public NotInheritable Class CompiledQuery
Visual Basic (Usage)
Dim instance As CompiledQuery
C#
public sealed class CompiledQuery
Visual C++
public ref class CompiledQuery sealed
J#
public final class CompiledQuery
JScript
public final class CompiledQuery

Provides for compilation and caching of queries for reuse. Conceptually this class contains a single Compile method with several overloads. You call the Compile method to create a new delegate to represent the compiled query. The delegate, when invoked with the ObjectContext input parameter and other parameter values, produces some result (such as an IQueryable<(Of <(T>)>) instance). The query is translated and cached when the delegate is invoked for the first time.

The following example compiles and then invokes a query that accepts DateTime and Decimal input parameters and returns a sequence of orders where the order date is later than March 8, 2003 and the total due is less than $300.00:

Visual Basic
ReadOnly s_compQuery5 = _
   CompiledQuery.Compile(Of AdventureWorksEntities, DateTime, Decimal, IQueryable(Of SalesOrderHeader))( _
                Function(ctx, orderDate, totalDue) From product In ctx.SalesOrderHeader _
                                                   Where Product.OrderDate > orderDate _
                                                      And Product.TotalDue < totalDue _
                                                   Order By Product.OrderDate _
                                                   Select Product)
Sub CompiledQuery5()

    Using AWEntities As New AdventureWorksEntities()

        Dim orderedAfterDate As DateTime = New DateTime(2003, 3, 8)
        Dim amountDue As Decimal = 300.0

        Dim orders As IQueryable(Of SalesOrderHeader) = _
            s_compQuery5.Invoke(AWEntities, orderedAfterDate, amountDue)

        For Each order In orders
            Console.WriteLine("ID: {0} Order date: {1} Total due: {2}", _
                              order.SalesOrderID, order.OrderDate, order.TotalDue)
        Next

    End Using
End Sub

C#
static readonly Func<AdventureWorksEntities, DateTime, Decimal, IQueryable<SalesOrderHeader>> s_compiledQuery5 = 
    CompiledQuery.Compile<AdventureWorksEntities, DateTime, Decimal, IQueryable<SalesOrderHeader>>(
            (ctx, orderDate, totalDue) => from product in ctx.SalesOrderHeader
                                          where product.OrderDate > orderDate 
                                             && product.TotalDue < totalDue
                                          orderby product.OrderDate
                                          select product);

static void CompiledQuery5()
{            
    using (AdventureWorksEntities AWEntities = new AdventureWorksEntities())
    {         
        DateTime date = new DateTime(2003, 3, 8);
        Decimal amountDue = 300.00M;

        IQueryable<SalesOrderHeader> orders = s_compiledQuery5.Invoke(AWEntities, date, amountDue);

        foreach (SalesOrderHeader order in orders)
        {
            Console.WriteLine("ID: {0} Order date: {1} Total due: {2}", order.SalesOrderID, order.OrderDate, order.TotalDue);
        }
    }            
}

System..::.Object
  System.Data.Objects..::.CompiledQuery
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5 SP1
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