SwitchExpression Class
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
Represents a control expression that handles multiple selections by passing control to SwitchCase.
Assembly: System.Core (in System.Core.dll)
The SwitchExpression type exposes the following members.
| 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.) |
![]() | Cases | Gets the collection of SwitchCase objects for the switch. |
![]() | Comparison | Gets the equality comparison method, if any. |
![]() | DefaultBody | Gets the test for the switch. |
![]() | NodeType | Returns the node type of this Expression. Extension nodes should return Extension when overriding this method. (Overrides Expression.NodeType.) |
![]() | SwitchValue | Gets the test for the switch. |
![]() | Type | Gets the static type of the expression that this Expression represents. (Overrides Expression.Type.) |
| Name | Description | |
|---|---|---|
![]() | Accept | Dispatches to the specific visit method for this node type. For example, MethodCallExpression calls the VisitMethodCall. (Inherited from Expression.) |
![]() | 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 the Object is reclaimed by garbage collection. (Inherited from Object.) |
![]() | GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
![]() | GetType | Gets the Type of the current instance. (Inherited from Object.) |
![]() | MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
![]() | 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.) |
![]() | Update | Creates a new expression that is like this one, but using the supplied children. If all of the children are the same, it will return this expression. |
![]() | VisitChildren | 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 an expression that represents a switch statement that has a default case by using the Switch method.
' Add the following directive to the file: ' Imports System.Linq.Expressions ' An expression that represents the switch value. Dim switchValue As ConstantExpression = Expression.Constant(3) ' This expression represents a switch statement ' that has a default case. Dim switchExpr As SwitchExpression = Expression.Switch( switchValue, Expression.Call( Nothing, GetType(Console).GetMethod("WriteLine", New Type() {GetType(String)}), Expression.Constant("Default") ), New SwitchCase() { Expression.SwitchCase( Expression.Call( Nothing, GetType(Console).GetMethod("WriteLine", New Type() {GetType(String)}), Expression.Constant("First") ), Expression.Constant(1) ), Expression.SwitchCase( Expression.Call( Nothing, GetType(Console).GetMethod("WriteLine", New Type() {GetType(String)}), Expression.Constant("Second") ), Expression.Constant(2) ) } ) ' The following statement first creates an expression tree, ' then compiles it, and then runs it. Expression.Lambda(Of Action)(switchExpr).Compile()() ' This code example produces the following output: ' ' Default
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