SwitchCase 类

定义

命名空间:
System.Linq.Expressions
程序集:
System.Core.dll, System.Linq.Expressions.dll
程序集:
netstandard.dll, System.Linq.Expressions.dll
程序集:
System.Linq.Expressions.dll
程序集:
System.Core.dll
程序集:
netstandard.dll
Source:
SwitchCase.cs
Source:
SwitchCase.cs
Source:
SwitchCase.cs
Source:
SwitchCase.cs
Source:
SwitchCase.cs

表示一个 SwitchExpression.

public ref class SwitchCase sealed
public sealed class SwitchCase
type SwitchCase = class
Public NotInheritable Class SwitchCase
继承
Object
SwitchCase

示例

以下示例演示如何使用该方法创建表示不带默认事例的 switch 语句的 SwitchCase 表达式。

// Add the following directive to the file:
// using System.Linq.Expressions;

// An expression that represents the switch value.
ConstantExpression switchValue = Expression.Constant(2);

// This expression represents a switch statement
// without a default case.
SwitchExpression switchExpr =
    Expression.Switch(
        switchValue,
        new SwitchCase[] {
            Expression.SwitchCase(
                Expression.Call(
                    null,
                    typeof(Console).GetMethod("WriteLine", new Type[] { typeof(String) }),
                    Expression.Constant("First")
                ),
                Expression.Constant(1)
            ),
            Expression.SwitchCase(
                Expression.Call(
                    null,
                    typeof(Console).GetMethod("WriteLine", new Type[] { typeof(String) }),
                    Expression.Constant("Second")
                ),
                Expression.Constant(2)
            )
        }
    );

// The following statement first creates an expression tree,
// then compiles it, and then runs it.
Expression.Lambda<Action>(switchExpr).Compile()();

// This code example produces the following output:
//
// Second

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

' An expression that represents the switch value.
Dim switchValue As ConstantExpression = Expression.Constant(2)

' This expression represents a switch statement 
' without a default case.
Dim switchExpr As SwitchExpression =
Expression.Switch(
    switchValue,
    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:
'
' Second

属性

名称 说明
Body

获取此事例的正文。
TestValues

获取此事例的值。 如果匹配其中任一值， SwitchValue 则会选择此情况以供执行。

方法

名称 说明
Equals(Object)

确定指定的对象是否等于当前对象。

(继承自 Object)
GetHashCode()

用作默认哈希函数。

(继承自 Object)
GetType()

获取当前实例的 Type。

(继承自 Object)
MemberwiseClone()

创建当前 Object的浅表副本。

(继承自 Object)
ToString()

返回一个 String 表示当前 Object类型的值。
Update(IEnumerable<Expression>, Expression)

创建类似于此表达式的新表达式，但使用提供的子级。 如果所有子级都相同，它将返回此表达式。

适用于