в 16:40, 26 мая 2010

2010-05-26T16:40:30Z

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2010-05-26T12:55:43Z

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==Hiding a member==

<source lang="vbnet">Public Class ClassX
Public s As String = "x"
End Class
Public Class ClassY
Inherits ClassX
Public Shadows s As String = "y"
Public Function getDerivedS() As String
Return s
End Function
Public Function getBaseS() As String
Return MyBase.s
End Function
End Class</source>

==Shadows Override==

<source lang="vbnet">Public Class ClassA
Public Function greet1() As String
Return "Hello from classA, Greet1 (no modifiers)"
End Function

Public Overridable Function greet2() As String
Return "Hello from classA, Greet2 (overridable)"
End Function
End Class
Public Class ClassB
Inherits ClassA

Public Shadows Function greet1() As String
Return "Hello from ClassB, Greet1 (shadows)"
End Function

Public Overrides Function greet2() As String
Return "Hello from ClassB, Greet2 (overrides)"
End Function
End Class</source>

==Test Shadows==

<source lang="vbnet">public class Test
public Shared Sub Main

Dim mgr As New Manager
mgr.FirstName = "Manager Last Name"
mgr.EmployeeId = 1

Dim emp As Employee = CType(mgr, Employee)
emp.FirstName = "Employee Last Name"
emp.EmployeeId = 2

Dim per As Person = CType(mgr, Person)
per.FirstName = "Person Last Name"
per.EmployeeId = "A"

Console.WriteLine(mgr.EmployeeId & ": " & mgr.FirstName)
Console.WriteLine(emp.EmployeeId & ": " & emp.FirstName)
Console.WriteLine(per.EmployeeId & ": " & per.FirstName)
End Sub
End class

Public Class Person
Public FirstName As String
Public EmployeeId As String
End Class
Public Class Employee
Inherits Person
Public Shadows EmployeeId As Long
End Class
Public Class Manager
Inherits Employee
Public Shadows FirstName As String
End Class</source>
<pre class=codeResult>2: Manager Last Name
2: Person Last Name
A: Person Last Name</pre>

==Use "Private Shadows" to hide member==

<source lang="vbnet">Public Class Base
Public Function Greet1() As String
Return "Greetings from Base"
End Function
End Class
Public Class Derived
Inherits Base
Private Shadows Function Greet1() As String
Return "Greetings from Base"
End Function
End Class
Public Class Morederived
Inherits Derived
End Class</source>

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VB.Net Tutorial/Class Module/Shadows - История изменений

в 16:40, 26 мая 2010

Admin: 1 версия