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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
Assemblies:   System.Core (in System.Core.dll)
  System.Linq.Expressions (in System.Linq.Expressions.dll)

'Declaration
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

.NET Framework

Supported in: 4.6, 4.5, 4

.NET Framework Client Profile

Supported in: 4

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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