Expression.MemberInit Method (NewExpression, array<MemberBinding[])

Parameters

• newExpression
  Type: System.Linq.Expressions.NewExpression
  A NewExpression to set the NewExpression property equal to.

• bindings
  Type: array<System.Linq.Expressions.MemberBinding[]
  An array of MemberBinding objects to use to populate the Bindings collection.

Return Value

Type: System.Linq.Expressions.MemberInitExpression
A MemberInitExpression that has the NodeType property equal to MemberInit and the NewExpression and Bindings properties set to the specified values.

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

   outputBlock.Text &= memberInitExpression.ToString() & vbCrLf

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

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

public static void CreateMemberInitExpression(System.Windows.Controls.TextBlock outputBlock)
{
   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);

   outputBlock.Text += memberInitExpression.ToString() + "\n";

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