Expression.Throw Method

Definition

Namespace:

System.Linq.Expressions

Assembly:

System.Linq.Expressions.dll

Creates a UnaryExpression that represents a throwing of an exception.

Overloads

Throw(Expression)	Creates a UnaryExpression that represents a throwing of an exception.
Throw(Expression, Type)	Creates a UnaryExpression that represents a throwing of an exception with a given type.

Throw(Expression)

Source:

UnaryExpression.cs

Creates a UnaryExpression that represents a throwing of an exception.

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

Parameters

value

Expression

An Expression.

Returns

UnaryExpression

A UnaryExpression that represents the exception.

Examples

The following example demonstrates how to create a TryExpression object that uses the Throw method.

// 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)

Source:

UnaryExpression.cs

Creates a UnaryExpression that represents a throwing of an exception with a given 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

Parameters

value

Expression

An Expression.

type

Type

The new Type of the expression.

Returns

UnaryExpression

A UnaryExpression that represents the exception.