Expression.PropertyOrField Method

Parameters

• expression
  Type: System.Linq.Expressions.Expression
  An Expression whose Type contains a property or field named propertyOrFieldName. This can be null for static members.

• propertyOrFieldName
  Type: System.String
  The name of a property or field to be accessed.

Return Value

Type: System.Linq.Expressions.MemberExpression
A MemberExpression that has the NodeType property equal to MemberAccess, the Expression property set to expression, and the Member property set to the PropertyInfo or FieldInfo that represents the property or field denoted by propertyOrFieldName.

' Add the following directive to your file:
' Imports System.Linq.Expressions  

Class TestClass
    Public Property Sample As Integer
End Class

Sub TestPropertyOrField()

    Dim obj As New TestClass()
    obj.Sample = 40

    ' This expression represents accessing a property or field.
    ' For static properties or fields, the first parameter must be Nothing.
    Dim memberExpr As Expression = Expression.PropertyOrField(
          Expression.Constant(obj),
          "Sample"
      )

    ' The following statement first creates an expression tree,
    ' then compiles it, and then runs it.
    outputBlock.Text &= Expression.Lambda(Of Func(Of Integer))(memberExpr).Compile()() & vbCrLf
End Sub

' This code example produces the following output:
'
' 40

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

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

    static void TestPropertyOrField(System.Windows.Controls.TextBlock outputBlock)
    {
       TestClass obj = new TestClass();
       obj.sample = 40;

       // This expression represents accessing a property or field.
       // For static properties or fields, the first parameter must be null.
       Expression memberExpr = Expression.PropertyOrField(
           Expression.Constant(obj),
           "sample"
       );

       // The following statement first creates an expression tree,
       // then compiles it, and then runs it.
       outputBlock.Text += Expression.Lambda<Func<int>>(memberExpr).Compile()() + "\n";
    }

    // This code example produces the following output:
    //
    // 40