Expression.Parameter Method (Type)

 

Creates a ParameterExpression node that can be used to identify a parameter or a variable in an expression tree.

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

Public Shared Function Parameter (
	type As Type
) As ParameterExpression

Parameters

type
Type: System.Type

The type of the parameter or variable.

Return Value

Type: System.Linq.Expressions.ParameterExpression

A ParameterExpression node with the specified name and type.

The following example demonstrates how to create a MethodCallExpression object that prints the value of a ParameterExpression object.

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

' Creating a parameter for the expression tree.
Dim param As ParameterExpression = Expression.Parameter(GetType(Integer))

' Creating an expression for the method call and specifying its parameter.
Dim methodCall As MethodCallExpression = Expression.Call(
        GetType(Console).GetMethod("WriteLine", New Type() {GetType(Integer)}),
        param
    )

' Compiling and invoking the methodCall expression.
Expression.Lambda(Of Action(Of Integer))(
    methodCall,
    New ParameterExpression() {param}
).Compile()(10)
' This code example produces the following output:
'
' 10

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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