Expression.TryCatch(Expression, CatchBlock[]) Method

Definition

Namespace:

System.Linq.Expressions

Assembly:

System.Linq.Expressions.dll

Source:

TryExpression.cs

Creates a TryExpression representing a try block with any number of catch statements and neither a fault nor finally block.

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

Parameters

body

Expression

The body of the try block.

handlers

CatchBlock[]

The array of zero or more CatchBlock expressions representing the catch statements to be associated with the try block.

Returns

TryExpression

The created TryExpression.

Examples

The following example demonstrates how to create a TryExpression object that contains a catch statement.

// 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