Expression.SwitchCase Método

Definición

Espacio de nombres:

System.Linq.Expressions

Ensamblado:

System.Linq.Expressions.dll

Ensamblado:

System.Core.dll

Ensamblado:

netstandard.dll

Crea un objeto SwitchCase que se va a usar en un objeto SwitchExpression.

Sobrecargas

SwitchCase(Expression, Expression[])	Crea un objeto SwitchCase que se va a usar en un objeto SwitchExpression.
SwitchCase(Expression, IEnumerable<Expression>)	Crea un objeto SwitchCase que se va a usar en un objeto SwitchExpression.

SwitchCase(Expression, Expression[])

Crea un objeto SwitchCase que se va a usar en un objeto SwitchExpression.

public:
 static System::Linq::Expressions::SwitchCase ^ SwitchCase(System::Linq::Expressions::Expression ^ body, ... cli::array <System::Linq::Expressions::Expression ^> ^ testValues);

public static System.Linq.Expressions.SwitchCase SwitchCase (System.Linq.Expressions.Expression body, params System.Linq.Expressions.Expression[] testValues);

static member SwitchCase : System.Linq.Expressions.Expression * System.Linq.Expressions.Expression[] -> System.Linq.Expressions.SwitchCase

Public Shared Function SwitchCase (body As Expression, ParamArray testValues As Expression()) As SwitchCase

Parámetros

body

Expression

Cuerpo del caso.

testValues

Expression[]

Valores de prueba del caso.

Devoluciones

SwitchCase

Objeto SwitchCase creado.

SwitchCase(Expression, IEnumerable<Expression>)

Crea un objeto SwitchCase que se va a usar en un objeto SwitchExpression.

public:
 static System::Linq::Expressions::SwitchCase ^ SwitchCase(System::Linq::Expressions::Expression ^ body, System::Collections::Generic::IEnumerable<System::Linq::Expressions::Expression ^> ^ testValues);

public static System.Linq.Expressions.SwitchCase SwitchCase (System.Linq.Expressions.Expression body, System.Collections.Generic.IEnumerable<System.Linq.Expressions.Expression> testValues);

static member SwitchCase : System.Linq.Expressions.Expression * seq<System.Linq.Expressions.Expression> -> System.Linq.Expressions.SwitchCase

Public Shared Function SwitchCase (body As Expression, testValues As IEnumerable(Of Expression)) As SwitchCase

Parámetros

body

Expression

Cuerpo del caso.

testValues

IEnumerable<Expression>

Valores de prueba del caso.

Devoluciones

SwitchCase

Objeto SwitchCase creado.

Ejemplos

En el ejemplo siguiente se muestra cómo crear una expresión que representa una instrucción switch que tiene un caso predeterminado.

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

// An expression that represents the switch value.
ConstantExpression switchValue = Expression.Constant(3);

// This expression represents a switch statement
// that has a default case.
SwitchExpression switchExpr =
    Expression.Switch(
        switchValue,
        Expression.Call(
                    null,
                    typeof(Console).GetMethod("WriteLine", new Type[] { typeof(String) }),
                    Expression.Constant("Default")
                ),
        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:
//
// Default

' 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

Comentarios

Todos los SwitchCase objetos de un SwitchExpression objeto deben tener el mismo tipo, a menos SwitchExpression que tenga el tipo void.

Cada SwitchCase objeto tiene una instrucción implícita break , lo que significa que no hay ninguna caída implícita de una etiqueta de mayúsculas y minúsculas a otra.