Expression.TryCatch(Expression, CatchBlock[]) Metode

Definisi

Ruang nama:

System.Linq.Expressions

Rakitan:

System.Linq.Expressions.dll

Sumber:

TryExpression.cs

TryExpression Membuat blok percobaan yang mewakili dengan sejumlah pernyataan tangkapan dan bukan kesalahan atau akhirnya memblokir.

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

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

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

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

Parameter

body

Expression

Isi blok percobaan.

handlers

CatchBlock[]

Array nol atau lebih CatchBlock ekspresi yang mewakili pernyataan tangkapan yang akan dikaitkan dengan blok coba.

Mengembalikan

TryExpression

Yang dibuat TryExpression.

Contoh

Contoh berikut menunjukkan cara membuat TryExpression objek yang berisi pernyataan tangkapan.

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

// A TryExpression object that has a Catch statement.
// The return types of the Try block and all Catch blocks must be the same.
TryExpression tryCatchExpr =
    Expression.TryCatch(
        Expression.Block(
            Expression.Throw(Expression.Constant(new DivideByZeroException())),
            Expression.Constant("Try 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:
//
// Catch block

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

' A TryExpression object that has a Catch statement.
' The return types of the Try block and all Catch blocks must be the same.
Dim tryCatchExpr As TryExpression =
       Expression.TryCatch(
           Expression.Block(
               Expression.Throw(Expression.Constant(New DivideByZeroException())),
               Expression.Constant("Try 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:
'
' Catch block