Expression.Throw Method (Expression)
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Creates a UnaryExpression that represents a throwing of an exception.
Namespace: System.Linq.Expressions
Assembly: System.Core (in System.Core.dll)
Syntax
'Declaration
Public Shared Function Throw ( _
value As Expression _
) As UnaryExpression
public static UnaryExpression Throw(
Expression value
)
Parameters
- value
Type: System.Linq.Expressions.Expression
An Expression.
Return Value
Type: System.Linq.Expressions.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:
' 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.
outputBlock.Text &= Expression.Lambda(Of Func(Of String))(tryCatchExpr).Compile()() & vbCrLf
' This code example produces the following output:
'
' Catch block
// 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.
outputBlock.Text += Expression.Lambda<Func<string>>(tryCatchExpr).Compile()() + "\n";
// This code example produces the following output:
//
// Catch block
Version Information
Silverlight
Supported in: 5, 4
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.