TypeFilter Delegar

Referência

Definição

Namespace:: System.Reflection

Assembly:: System.Runtime.dll

Assembly:: System.Reflection.dll

Assembly:: mscorlib.dll

Assembly:: netstandard.dll

Importante

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Filtra as classes representadas em uma matriz de objetos Type.

public delegate bool TypeFilter(Type ^ m, System::Object ^ filterCriteria);

public delegate bool TypeFilter(Type m, object? filterCriteria);

public delegate bool TypeFilter(Type m, object filterCriteria);

[System.Serializable]
public delegate bool TypeFilter(Type m, object filterCriteria);

[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public delegate bool TypeFilter(Type m, object filterCriteria);

type TypeFilter = delegate of Type * obj -> bool

[<System.Serializable>]
type TypeFilter = delegate of Type * obj -> bool

[<System.Serializable>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type TypeFilter = delegate of Type * obj -> bool

Public Delegate Function TypeFilter(m As Type, filterCriteria As Object) As Boolean

Parâmetros

m: Type

O objeto Type ao qual o filtro é aplicado.

filterCriteria: Object

Um objeto arbitrário usado para filtrar a lista.

Valor Retornado

Boolean

true para incluir o Type na lista filtrada; caso contrário, false.

Atributos: SerializableAttribute ComVisibleAttribute

Exemplos

Este exemplo mostra como definir um método que corresponda ao TypeFilter protótipo delegado, permitindo que você use reflexão para filtrar ou retornar um subconjunto de entradas correspondentes.

Imports System.Reflection

' This interface is defined in this assembly.
Public Interface IBookRetailer
    Sub Purchase()
    Sub ApplyDiscount()
End Interface

' This interface is also defined in this assembly.
Public Interface IMusicRetailer
    Sub Purchase()
End Interface

' This class implements three interfaces;
'    Two are defined in this assembly.
'    One is defined in another assembly.
Public Class MyRetailer
    Implements IBookRetailer, IMusicRetailer, IComparable

    ' For demonstration purposes, this method returns nothing.
    Public Function CompareTo(ByVal obj As Object) As Integer Implements System.IComparable.CompareTo
        Return Nothing
    End Function

    ' For demonstration purposes only, this method does nothing.
    Public Sub ApplyDiscount() Implements IBookRetailer.ApplyDiscount
    End Sub

    ' For demonstration purposes only, this method does nothing.
    Public Sub Purchase() Implements IBookRetailer.Purchase
    End Sub

    ' For demonstration purposes only, this method does nothing.
    Public Sub Purchase1() Implements IMusicRetailer.Purchase
    End Sub
End Class

Module Module1
    Sub Main()
        ' Find the interfaces defined by the MyRetailer class. Each interface found is passed to
        ' the TypeFilter method which checks if the interface is defined in the executing assembly.
        Dim retailerType As Type = GetType(MyRetailer)
        Dim interfaces() As Type = _
            retailerType.FindInterfaces(AddressOf TypeFilter, retailerType.Assembly.GetName().ToString())

        ' Show the interfaces that are defined in this assembly that are also implemented by MyRetailer.
        Console.WriteLine("MyRetailer implements the following interfaces (defined in this assembly):")
        For Each t In interfaces
            Console.WriteLine("   {0}", t.Name)
        Next
    End Sub

    ' This method is called by the FindInterfaces method. 
    ' This method is called once per defined interface.
    Function TypeFilter(ByVal t As Type, ByVal filterCriteria As Object) As Boolean
        ' Return true if interface is defined in the same 
        ' assembly identified by the filterCriteria object.
        Return t.Assembly.GetName().ToString() = CType(filterCriteria, String)
    End Function
End Module
' The example displays the following output:
'    MyRetailer implements the following interfaces (defined in this assembly):
'      IBookRetailer
'      IMusicRetailer

Comentários

O TypeFilter delegado é usado para filtrar uma lista de classes. Especificamente, você o usa para filtrar as classes representadas em uma matriz de Type objetos. O Type.FindInterfaces método usa esse delegado para filtrar a lista de interfaces retornada. Cada classe derivada e Delegate MulticastDelegate tem um construtor e um DynamicInvoke método. Consulte o exemplo de código do Visual C++ dado na descrição para Delegate.

Métodos de Extensão

GetMethodInfo(Delegate)

Obtém um objeto que representa o método representado pelo delegado especificado.

Aplica-se a