TypeFilter Delegasikan

Definisi

Ruang nama:

System.Reflection

Rakitan:

System.Runtime.dll

Memfilter kelas yang diwakili dalam array Type objek.

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

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

type TypeFilter = delegate of Type * obj -> bool

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

Parameter

m

Type

Objek Type tempat filter diterapkan.

filterCriteria

Object

Objek arbitrer yang digunakan untuk memfilter daftar.

Tampilkan Nilai

Boolean

true untuk menyertakan Type dalam daftar yang difilter; jika tidak false.

Contoh

Contoh ini menunjukkan cara menentukan metode yang cocok dengan TypeFilter prototipe delegasi yang memungkinkan Anda menggunakan pantulan untuk memfilter atau mengembalikan subset entri yang cocok.

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

Keterangan

Delegasi TypeFilter digunakan untuk memfilter daftar kelas. Secara khusus, Anda menggunakannya untuk memfilter kelas yang diwakili dalam array Type objek. Metode ini Type.FindInterfaces menggunakan delegasi ini untuk memfilter daftar antarmuka yang dikembalikannya. Setiap kelas turunan dan DelegateMulticastDelegate memiliki konstruktor dan DynamicInvoke metode . Lihat contoh kode Visual C++ yang diberikan dalam deskripsi untuk Delegate.

Metode Ekstensi

GetMethodInfo(Delegate)

Mendapatkan objek yang mewakili metode yang diwakili oleh delegasi yang ditentukan.

Lihat juga

• FindInterfaces(TypeFilter, Object)
• Object
• Delegate
• MulticastDelegate