Expression.Parameter Method (Type)
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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)
Syntax
'Declaration
Public Shared Function Parameter ( _
type As Type _
) As ParameterExpression
public static ParameterExpression Parameter(
Type type
)
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.
Examples
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
// Add the following directive to the file:
// using System.Linq.Expressions;
// Creating a parameter for the expression tree.
ParameterExpression param = Expression.Parameter(typeof(int));
// Creating an expression for the method call and specifying its parameter.
MethodCallExpression methodCall = Expression.Call(
typeof(Console).GetMethod("WriteLine", new Type[] { typeof(int) }),
param
);
// The following statement first creates an expression tree,
// then compiles it, and then runs it.
Expression.Lambda<Action<int>>(
methodCall,
new ParameterExpression[] { param }
).Compile()(10);
// This code example produces the following output:
//
// 10
Version Information
Silverlight
Supported in: 5, 4
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.