VB.Net/Language Basics/Attribute — различия между версиями

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Текущая версия на 12:42, 26 мая 2010

Define and use Attribute to track bugs

Imports System
Imports System.Reflection
 
Public Class MainClass
    Shared Sub Main(  )
         Dim mm As New MyMath(  )
         Console.WriteLine("Calling DoFunc(10). Result: {0}", mm.DoFunc1(10))
         Dim inf As System.Reflection.MemberInfo = GetType(MyMath)
         Dim attributes(  ) As Attribute
         attributes = _
            inf.GetCustomAttributes(GetType(BugFixAttribute), False)
         Dim attribute As [Object]
         For Each attribute In attributes
             Dim bfa As BugFixAttribute = CType(attribute, BugFixAttribute)
             Console.WriteLine(ControlChars.Lf + "BugID: {0}", bfa.BugID)
             Console.WriteLine("Programmer: {0}", bfa.Programmer)
             Console.WriteLine("Date: {0}", bfa.theDate)
             Console.WriteLine("Comment: {0}", bfa.rument)
         Next attribute
    End Sub
  
End Class
  
 <AttributeUsage(AttributeTargets.Class Or _
 AttributeTargets.Constructor Or _
 AttributeTargets.Field Or _
 AttributeTargets.Method Or _
 AttributeTargets.Property, AllowMultiple:=True)> _
 Public Class BugFixAttribute
     Inherits System.Attribute
     Private mBugID As Integer
     Private mComment As String
     Private mDate As String
     Private mProgrammer As String
     Public Sub New( _
         ByVal bugID As Integer, _
         ByVal programmer As String, _
         ByVal theDate As String)
         mBugID = bugID
         mProgrammer = programmer
         mDate = theDate
     End Sub
     Public ReadOnly Property BugID(  ) As Integer
         Get
             Return mBugID
         End Get
     End Property
     Public Property Comment(  ) As String
         Get
             Return mComment
         End Get
         Set(ByVal Value As String)
             mComment = Value
         End Set
     End Property
     Public ReadOnly Property theDate(  ) As String
         Get
             Return mDate
         End Get
     End Property
     Public ReadOnly Property Programmer(  ) As String
         Get
             Return mProgrammer
         End Get
     End Property
 End Class
 <BugFixAttribute(121, "James Band", "07/07/07", _
  Comment:="Fixed one error")> _
 Public Class MyMath
     Public Function DoFunc1(ByVal param1 As Double) As Double
         Return param1 
     End Function
 End Class


Obsolete attribute

Imports System
Imports System.Text
Imports System.Text.RegularExpressions

Public Class MainClass
    Shared Sub Main(  )
       Dim d As Demo = New Demo()
       d.Method1()
    End Sub "Main
   
End Class
  <Serializable()> Public Class Demo
    <Obsolete("Use Method2 instead.")> Public Sub Method1()
    End Sub
    <System.ObsoleteAttribute("Use Method2 instead.", True)> Public Sub Method2()
      "Old implementation
    End Sub
    Public Sub Method3()
      " New implementation ...
    End Sub
  End Class
  <Serializable(), Obsolete("No longer used.")> Public Class Test
  End Class