Expression.TryCatchFinally(Expression, Expression, CatchBlock[]) Método

Definición

Espacio de nombres:

System.Linq.Expressions

Ensamblado:

System.Linq.Expressions.dll

Source:

TryExpression.cs

Crea un objeto TryExpression que representa un bloque try con cualquier número de instrucciones Catch y un bloque finally.

public:
 static System::Linq::Expressions::TryExpression ^ TryCatchFinally(System::Linq::Expressions::Expression ^ body, System::Linq::Expressions::Expression ^ finally, ... cli::array <System::Linq::Expressions::CatchBlock ^> ^ handlers);

public static System.Linq.Expressions.TryExpression TryCatchFinally (System.Linq.Expressions.Expression body, System.Linq.Expressions.Expression? finally, params System.Linq.Expressions.CatchBlock[]? handlers);

static member TryCatchFinally : System.Linq.Expressions.Expression * System.Linq.Expressions.Expression * System.Linq.Expressions.CatchBlock[] -> System.Linq.Expressions.TryExpression

Public Shared Function TryCatchFinally (body As Expression, finally As Expression, ParamArray handlers As CatchBlock()) As TryExpression

Parámetros

body

Expression

Cuerpo del bloque try.

finally

Expression

Cuerpo del bloque finally.

handlers

CatchBlock[]

Matriz de cero o más expresiones CatchBlock que representa las instrucciones Catch que se van a asociar al bloque try.

Devoluciones

TryExpression

Objeto TryExpression creado.

Ejemplos

En el ejemplo siguiente se muestra cómo crear un TryExpression objeto que contiene una instrucción catch y una instrucción finally.

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

// A TryExpression object that has a catch statement and a finally statement.
// The return types of the try block and all catch blocks must be the same.
TryExpression tryCatchExpr =
    Expression.TryCatchFinally(
        Expression.Block(
            Expression.Throw(Expression.Constant(new DivideByZeroException())),
            Expression.Constant("Try block")
        ),
        Expression.Call(typeof(Console).GetMethod("WriteLine", new Type[] { typeof(string) }), Expression.Constant("Finally block")),
        Expression.Catch(
            typeof(DivideByZeroException),
            Expression.Constant("Catch block")
        )
    );

// The following statement first creates an expression tree,
// then compiles it, and then runs it.
// If the exception is caught,
// the result of the TryExpression is the last statement
// of the corresponding catch statement.
Console.WriteLine(Expression.Lambda<Func<string>>(tryCatchExpr).Compile()());

// This code example produces the following output:
//
// Finally block
// Catch block

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

' A TryExpression object that has a catch statement and a finally statement.
' The return types of the try block and all catch blocks must be the same.
Dim tryCatchExpr As TryExpression =
    Expression.TryCatchFinally(
        Expression.Block(
            Expression.Throw(Expression.Constant(New DivideByZeroException())),
            Expression.Constant("Try block")
         ),
    Expression.Call(
        GetType(Console).GetMethod("WriteLine", New Type() {GetType(String)}),
        Expression.Constant("Finally block")
    ),
    Expression.Catch(
        GetType(DivideByZeroException),
        Expression.Constant("Catch block")
    )
)

' The following statement first creates an expression tree,
' then compiles it, and then runs it.
' If the exception is caught, 
' the result of the TryExpression is the last statement 
' of the corresponding catch statement.
Console.WriteLine(Expression.Lambda(Of Func(Of String))(tryCatchExpr).Compile()())

' This code example produces the following output:
'
' Finally block
' Catch block