Expression.MemberInit Metoda

Definice

Obor názvů:

System.Linq.Expressions

Sestavení:

netstandard.dll, System.Linq.Expressions.dll

Představuje výraz, který vytvoří nový objekt a inicializuje vlastnost objektu.

Přetížení

Name	Description
MemberInit(NewExpression, IEnumerable<MemberBinding>)	Představuje výraz, který vytvoří nový objekt a inicializuje vlastnost objektu.
MemberInit(NewExpression, MemberBinding[])	Vytvoří MemberInitExpression.

MemberInit(NewExpression, IEnumerable<MemberBinding>)

Zdroj:

MemberInitExpression.cs

Představuje výraz, který vytvoří nový objekt a inicializuje vlastnost objektu.

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

Public Shared Function MemberInit (newExpression As NewExpression, bindings As IEnumerable(Of MemberBinding)) As MemberInitExpression

Parametry

newExpression

NewExpression

A NewExpression nastavit NewExpression vlastnost rovná se.

bindings

IEnumerable<MemberBinding>

Objekt IEnumerable<T> obsahující MemberBinding objekty, které se mají použít k naplnění Bindings kolekce.

Návraty

MemberInitExpression

AMemberInitExpression, který má vlastnost rovna MemberInitNodeType a NewExpression a Bindings vlastnosti nastaveny na zadané hodnoty.

Výjimky

ArgumentNullException

newExpression nebo bindings je null.

ArgumentException

Vlastnost Member elementu bindings nepředstavuje člena typu, který newExpression. Typ představuje.

Příklady

Následující příklad ukazuje výraz, který vytvoří nový objekt a inicializuje vlastnost objektu.

// 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

Poznámky

Vlastnost Type výsledného MemberInitExpression je rovna Type vlastnosti newExpression.

MemberInit(NewExpression, MemberBinding[])

Zdroj:

MemberInitExpression.cs

Vytvoří 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

Public Shared Function MemberInit (newExpression As NewExpression, ParamArray bindings As MemberBinding()) As MemberInitExpression

Parametry

newExpression

NewExpression

A NewExpression nastavit NewExpression vlastnost rovná se.

bindings

MemberBinding[]

Pole MemberBinding objektů, které se mají použít k naplnění Bindings kolekce.

Návraty

MemberInitExpression

AMemberInitExpression, který má vlastnost rovna MemberInitNodeType a NewExpression a Bindings vlastnosti nastaveny na zadané hodnoty.

Výjimky

ArgumentNullException

newExpression nebo bindings je null.

ArgumentException

Vlastnost Member elementu bindings nepředstavuje člena typu, který newExpression. Typ představuje.

Příklady

Následující příklad ukazuje, jak použít metodu MemberInit(NewExpression, MemberBinding[]) k vytvoření MemberInitExpression , která představuje inicializaci dvou členů nového objektu.

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

Poznámky

Vlastnost Type výsledného MemberInitExpression je rovna Type vlastnosti newExpression.