Expression.MemberInit Метод

Определение

Представляет выражение, создающее новый объект и инициализирующее свойство объекта.Represents an expression that creates a new object and initializes a property of the object.

Перегрузки

MemberInit(NewExpression, IEnumerable<MemberBinding>)

Представляет выражение, создающее новый объект и инициализирующее свойство объекта.Represents an expression that creates a new object and initializes a property of the object.

MemberInit(NewExpression, MemberBinding[])

Создает объект MemberInitExpression.Creates a MemberInitExpression.

MemberInit(NewExpression, IEnumerable<MemberBinding>)

Представляет выражение, создающее новый объект и инициализирующее свойство объекта.Represents an expression that creates a new object and initializes a property of the object.

public:
 static System::Linq::Expressions::MemberInitExpression ^ MemberInit(System::Linq::Expressions::NewExpression ^ newExpression, System::Collections::Generic::IEnumerable<System::Linq::Expressions::MemberBinding ^> ^ bindings);
public static System.Linq.Expressions.MemberInitExpression MemberInit (System.Linq.Expressions.NewExpression newExpression, System.Collections.Generic.IEnumerable<System.Linq.Expressions.MemberBinding> bindings);
static member MemberInit : System.Linq.Expressions.NewExpression * seq<System.Linq.Expressions.MemberBinding> -> System.Linq.Expressions.MemberInitExpression

Параметры

newExpression
NewExpression

Объект NewExpression, который следует задать в качестве значения свойства NewExpression.A NewExpression to set the NewExpression property equal to.

bindings
IEnumerable<MemberBinding>

IEnumerable<T>, содержащий все объекты MemberBinding, используемые для заполнения коллекции Bindings.An IEnumerable<T> that contains MemberBinding objects to use to populate the Bindings collection.

Возвраты

Выражение MemberInitExpression со свойствомNodeType, равным MemberInit, и свойствами NewExpression и Bindings, для которых заданы указанные значения.A MemberInitExpression that has the NodeType property equal to MemberInit and the NewExpression and Bindings properties set to the specified values.

Исключения

Параметр newExpression или bindings имеет значение null.newExpression or bindings is null.

Свойство Member элемента bindings не представляет элемент типа поля или свойства, который представляет newExpression.Type.The Member property of an element of bindings does not represent a member of the type that newExpression.Type represents.

Примеры

В следующем примере показано выражение, которое создает новый объект и инициализирует свойство объекта.The following example demonstrates an expression that creates a new object and initializes a property of the object.


// Add the following directive to your file:
// using System.Linq.Expressions;  

class TestMemberInitClass
{
    public int sample { get; set; }
}

static void MemberInit()
{   
    // This expression creates a new TestMemberInitClass object
    // and assigns 10 to its sample property.
    Expression testExpr = Expression.MemberInit(
        Expression.New(typeof(TestMemberInitClass)),
        new List<MemberBinding>() {
            Expression.Bind(typeof(TestMemberInitClass).GetMember("sample")[0], Expression.Constant(10))
        }
    );

    // The following statement first creates an expression tree,
    // then compiles it, and then runs it.
    var test = Expression.Lambda<Func<TestMemberInitClass>>(testExpr).Compile()();
    Console.WriteLine(test.sample);
}

// This code example produces the following output:
//
// 10
' Add the following directive to your file:
' Imports System.Linq.Expressions  

Class TestMemberInitClass
    Public Property Sample As Integer
End Class

Sub MemberInit()
    ' This expression creates a new TestMemberInitClass object
    ' and assigns 10 to its Sample property.
    Dim testExpr As Expression = Expression.MemberInit(
        Expression.[New](GetType(TestMemberInitClass)),
        New List(Of MemberBinding)() From {
            Expression.Bind(GetType(TestMemberInitClass).GetMember("Sample")(0), Expression.Constant(10))
        }
    )

    ' The following statement first creates an expression tree,
    ' then compiles it, and then runs it.
    Dim test = Expression.Lambda(Of Func(Of TestMemberInitClass))(testExpr).Compile()()
    Console.WriteLine(test.Sample)
End Sub

' This code example produces the following output:
'
' 10

Комментарии

Свойство результирующего MemberInitExpression объекта равно Type свойству объекта newExpression. TypeThe Type property of the resulting MemberInitExpression is equal to the Type property of newExpression.

MemberInit(NewExpression, MemberBinding[])

Создает объект MemberInitExpression.Creates a MemberInitExpression.

public:
 static System::Linq::Expressions::MemberInitExpression ^ MemberInit(System::Linq::Expressions::NewExpression ^ newExpression, ... cli::array <System::Linq::Expressions::MemberBinding ^> ^ bindings);
public static System.Linq.Expressions.MemberInitExpression MemberInit (System.Linq.Expressions.NewExpression newExpression, params System.Linq.Expressions.MemberBinding[] bindings);
static member MemberInit : System.Linq.Expressions.NewExpression * System.Linq.Expressions.MemberBinding[] -> System.Linq.Expressions.MemberInitExpression

Параметры

newExpression
NewExpression

Объект NewExpression, который следует задать в качестве значения свойства NewExpression.A NewExpression to set the NewExpression property equal to.

bindings
MemberBinding[]

Массив объектов MemberBinding для заполнения коллекции Bindings.An array of MemberBinding objects to use to populate the Bindings collection.

Возвраты

Выражение MemberInitExpression со свойствомNodeType, равным MemberInit, и свойствами NewExpression и Bindings, для которых заданы указанные значения.A MemberInitExpression that has the NodeType property equal to MemberInit and the NewExpression and Bindings properties set to the specified values.

Исключения

Параметр newExpression или bindings имеет значение null.newExpression or bindings is null.

Свойство Member элемента bindings не представляет элемент типа поля или свойства, который представляет newExpression.Type.The Member property of an element of bindings does not represent a member of the type that newExpression.Type represents.

Примеры

В следующем примере демонстрируется использование MemberInit(NewExpression, MemberBinding[]) метода для MemberInitExpression создания объекта, представляющего инициализацию двух членов нового объекта.The following example demonstrates how to use the MemberInit(NewExpression, MemberBinding[]) method to create a MemberInitExpression that represents the initialization of two members of a new object.

class Animal
{
    public string Species {get; set;}
    public int Age {get; set;}
}

public static void CreateMemberInitExpression()
{
    System.Linq.Expressions.NewExpression newAnimal =
        System.Linq.Expressions.Expression.New(typeof(Animal));

    System.Reflection.MemberInfo speciesMember =
        typeof(Animal).GetMember("Species")[0];
    System.Reflection.MemberInfo ageMember =
        typeof(Animal).GetMember("Age")[0];

    // Create a MemberBinding object for each member
    // that you want to initialize.
    System.Linq.Expressions.MemberBinding speciesMemberBinding =
        System.Linq.Expressions.Expression.Bind(
            speciesMember,
            System.Linq.Expressions.Expression.Constant("horse"));
    System.Linq.Expressions.MemberBinding ageMemberBinding =
        System.Linq.Expressions.Expression.Bind(
            ageMember,
            System.Linq.Expressions.Expression.Constant(12));

    // Create a MemberInitExpression that represents initializing
    // two members of the 'Animal' class.
    System.Linq.Expressions.MemberInitExpression memberInitExpression =
        System.Linq.Expressions.Expression.MemberInit(
            newAnimal,
            speciesMemberBinding,
            ageMemberBinding);

    Console.WriteLine(memberInitExpression.ToString());

    // This code produces the following output:
    //
    // new Animal() {Species = "horse", Age = 12}
}
Class Animal
    Public Species As String
    Public Age As Integer
End Class

Shared Sub CreateMemberInitExpression()
    Dim newAnimal As System.Linq.Expressions.NewExpression = _
        System.Linq.Expressions.Expression.[New](Type.GetType("ExpressionVB.MemberInitExample+Animal"))

    Dim speciesMember As System.Reflection.MemberInfo = _
        Type.GetType("ExpressionVB.MemberInitExample+Animal").GetMember("Species")(0)
    Dim ageMember As System.Reflection.MemberInfo = _
        Type.GetType("ExpressionVB.MemberInitExample+Animal").GetMember("Age")(0)

    ' Create a MemberBinding object for each member
    ' that you want to initialize.
    Dim speciesMemberBinding As System.Linq.Expressions.MemberBinding = _
        System.Linq.Expressions.Expression.Bind( _
            speciesMember, _
            System.Linq.Expressions.Expression.Constant("horse"))
    Dim ageMemberBinding As System.Linq.Expressions.MemberBinding = _
        System.Linq.Expressions.Expression.Bind( _
            ageMember, _
            System.Linq.Expressions.Expression.Constant(12))

    ' Create a MemberInitExpression that represents initializing
    ' two members of the 'Animal' class.
    Dim memberInitExpression As System.Linq.Expressions.MemberInitExpression = _
        System.Linq.Expressions.Expression.MemberInit( _
            newAnimal, _
            speciesMemberBinding, _
            ageMemberBinding)

    Console.WriteLine(memberInitExpression.ToString())

    ' This code produces the following output:
    '
    ' new Animal() {Species = "horse", Age = 12}
End Sub

Комментарии

Свойство результирующего MemberInitExpression объекта равно Type свойству объекта newExpression. TypeThe Type property of the resulting MemberInitExpression is equal to the Type property of newExpression.

Применяется к