Expression.Call Method (Expression, MethodInfo, Expression, Expression)

 

Creates a MethodCallExpression that represents a call to a method that takes two arguments.

Namespace:   System.Linq.Expressions
Assembly:  System.Core (in System.Core.dll)

Public Shared Function Call (
	instance As Expression,
	method As MethodInfo,
	arg0 As Expression,
	arg1 As Expression
) As MethodCallExpression

Parameters

instance
Type: System.Linq.Expressions.Expression

An Expression that specifies the instance for an instance call. (pass null for a static (Shared in Visual Basic) method).

method
Type: System.Reflection.MethodInfo

The MethodInfo that represents the target method.

arg0
Type: System.Linq.Expressions.Expression

The Expression that represents the first argument.

arg1
Type: System.Linq.Expressions.Expression

The Expression that represents the second argument.

Return Value

Type: System.Linq.Expressions.MethodCallExpression

A MethodCallExpression that has the NodeType property equal to Call and the Object and Method properties set to the specified values.

The following code example shows how to create an expression that calls an instance method that has two arguments.

' Add the following directive to your file:
' Imports System.Linq.Expressions  
Public Class SampleClass
    Public Function AddIntegers(ByVal arg1 As Integer, ByVal arg2 As Integer) As Integer
        Return (arg1 + arg2)
    End Function
End Class
Public Shared Sub TestCall()
    ' This expression represents a call to an instance method that has two arguments.
    ' The first argument is an expression that creates a new object of the specified type.
    Dim callExpr As Expression = Expression.Call(
        Expression.[New](GetType(SampleClass)),
        GetType(SampleClass).GetMethod("AddIntegers", New Type() {GetType(Integer), GetType(Integer)}),
        Expression.Constant(1),
        Expression.Constant(2)
      )

    ' Print the expression.
    Console.WriteLine(callExpr.ToString())

    ' The following statement first creates an expression tree,
    ' then compiles it, and then executes it.
    Console.WriteLine(Expression.Lambda(Of Func(Of Integer))(callExpr).Compile()())
End Sub

' This code example produces the following output:
'
' new SampleClass().AddIntegers(1, 2)
' 3

Universal Windows Platform
Available since 8
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 4.0
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1
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