Label Method (Type)
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Expression.Label Method (Type)

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

Creates a LabelTarget representing a label with the given type.

Namespace:  System.Linq.Expressions
Assembly:  System.Core (in System.Core.dll)

'Declaration
Public Shared Function Label ( _
	type As Type _
) As LabelTarget

Parameters

type
Type: System.Type
The type of value that is passed when jumping to the label.

Return Value

Type: System.Linq.Expressions.LabelTarget
The new LabelTarget representing a label with the given type.

The following example demonstrates how to use a LabelTarget object in a loop expression.


' Add the following directive to the file:
' Imports System.Linq.Expressions  
' Creating a parameter expression.
Dim value As ParameterExpression =
    Expression.Parameter(GetType(Integer), "value")

' Creating an expression to hold a local variable. 
Dim result As ParameterExpression =
    Expression.Parameter(GetType(Integer), "result")

' Creating a label to jump to from a loop.
Dim label As LabelTarget = Expression.Label(GetType(Integer))

' Creating a method body.
Dim block As BlockExpression = Expression.Block(
    New ParameterExpression() {result},
    Expression.Assign(result, Expression.Constant(1)),
    Expression.Loop(
        Expression.IfThenElse(
            Expression.GreaterThan(value, Expression.Constant(1)),
            Expression.MultiplyAssign(result,
                Expression.PostDecrementAssign(value)),
            Expression.Break(label, result)
        ),
        label
    )
)

' Compile an expression tree and return a delegate.
Dim factorial As Integer =
    Expression.Lambda(Of Func(Of Integer, Integer))(block, value).Compile()(5)

outputBlock.Text &= factorial & vbCrLf

' This code example produces the following output:
'
' 120


Windows Phone OS

Supported in: 8.1, 8.0

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