Expression.Throw Metodo

Definizione

Spazio dei nomi:

System.Linq.Expressions

Assembly:

System.Linq.Expressions.dll

Crea un oggetto UnaryExpression che rappresenta la generazione di un'eccezione.

Overload

Throw(Expression)	Crea un oggetto UnaryExpression che rappresenta la generazione di un'eccezione.
Throw(Expression, Type)	Crea un oggetto UnaryExpression che rappresenta la generazione di un'eccezione con un tipo specificato.

Throw(Expression)

Origine:

UnaryExpression.cs

Crea un oggetto UnaryExpression che rappresenta la generazione di un'eccezione.

public:
 static System::Linq::Expressions::UnaryExpression ^ Throw(System::Linq::Expressions::Expression ^ value);

public static System.Linq.Expressions.UnaryExpression Throw (System.Linq.Expressions.Expression? value);

static member Throw : System.Linq.Expressions.Expression -> System.Linq.Expressions.UnaryExpression

Public Shared Function Throw (value As Expression) As UnaryExpression

Parametri

value

Expression

Oggetto Expression.

Restituisce

UnaryExpression

Oggetto UnaryExpression che rappresenta l'eccezione.

Esempio

Nell'esempio seguente viene illustrato come creare un TryExpression oggetto che usa il Throw metodo .

// 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

Throw(Expression, Type)

Origine:

UnaryExpression.cs

Crea un oggetto UnaryExpression che rappresenta la generazione di un'eccezione con un tipo specificato.

public:
 static System::Linq::Expressions::UnaryExpression ^ Throw(System::Linq::Expressions::Expression ^ value, Type ^ type);

public static System.Linq.Expressions.UnaryExpression Throw (System.Linq.Expressions.Expression? value, Type type);

static member Throw : System.Linq.Expressions.Expression * Type -> System.Linq.Expressions.UnaryExpression

Public Shared Function Throw (value As Expression, type As Type) As UnaryExpression

Parametri

value

Expression

Oggetto Expression.

type

Type

Nuovo oggetto Type dell'espressione.

Restituisce

UnaryExpression

Oggetto UnaryExpression che rappresenta l'eccezione.