Expression.Throw 方法

定义

创建一个 UnaryExpression,它表示引发异常。

重载

Throw(Expression)

创建一个 UnaryExpression,它表示引发异常。

Throw(Expression, Type)

创建一个 UnaryExpression,它表示引发具有给定类型的异常。

Throw(Expression)

创建一个 UnaryExpression,它表示引发异常。

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

参数

返回

一个表示异常的 UnaryExpression

示例

下面的示例演示如何创建 TryExpression 使用 Throw 方法的 对象。

// 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

适用于

Throw(Expression, Type)

创建一个 UnaryExpression,它表示引发具有给定类型的异常。

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);
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

参数

type
Type

表达式的新 Type

返回

一个表示异常的 UnaryExpression

适用于