ParameterExpression Class
Represents a named parameter expression.
Assembly: System.Core (in System.Core.dll)
| Name | Description | |
|---|---|---|
![]() | CanReduce | Indicates that the node can be reduced to a simpler node. If this returns true, Reduce() can be called to produce the reduced form.(Inherited from Expression.) |
![]() | IsByRef | Indicates that this ParameterExpression is to be treated as a ByRef parameter. |
![]() | Name | Gets the name of the parameter or variable. |
![]() | NodeType | Returns the node type of this Expression.(Overrides Expression.NodeType.) |
![]() | Type | Gets the static type of the expression that this Expression represents.(Overrides Expression.Type.) |
| Name | Description | |
|---|---|---|
![]() | Accept(ExpressionVisitor) | Dispatches to the specific visit method for this node type. For example, MethodCallExpression calls the VisitMethodCall.(Overrides Expression.Accept(ExpressionVisitor).) |
![]() | Equals(Object) | Determines whether the specified object is equal to the current object.(Inherited from Object.) |
![]() | Finalize() | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.) |
![]() | GetHashCode() | Serves as the default hash function. (Inherited from Object.) |
![]() | GetType() | |
![]() | MemberwiseClone() | |
![]() | Reduce() | Reduces this node to a simpler expression. If CanReduce returns true, this should return a valid expression. This method can return another node which itself must be reduced.(Inherited from Expression.) |
![]() | ReduceAndCheck() | Reduces this node to a simpler expression. If CanReduce returns true, this should return a valid expression. This method can return another node which itself must be reduced.(Inherited from Expression.) |
![]() | ReduceExtensions() | Reduces the expression to a known node type (that is not an Extension node) or just returns the expression if it is already a known type.(Inherited from Expression.) |
![]() | ToString() | Returns a textual representation of the Expression.(Inherited from Expression.) |
![]() | VisitChildren(ExpressionVisitor) | Reduces the node and then calls the visitor delegate on the reduced expression. The method throws an exception if the node is not reducible.(Inherited from Expression.) |
The following example demonstrates how to create a MethodCallExpression object that prints the value of a ParameterExpression object by using the Parameter method.
' 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
Available since 8
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.


