VB.NET：使用 Class 名称作为表达式

Question

I'm not sure if this is possible but I would like to associate a class name reference to a shared member method / property / variable. Consider:

Public Class UserParameters

    Public Shared Reference As Object

    Public Shared Function GetReference() As Object
        Return Reference
    End Function

End Class

In another part of the program I would like to simply call UserParameters and have it return Reference either by aliasing GetReference or the variable directly.

I am trying to emulate the Application, Request, or Session variable: Session(0) = Session.Item(0)

Any suggestions would be greatly appreciated.

Answer 1

You can't return an instance member from a static method directly (the static method can't access instance members because it isn't instantiated with the rest of the class, only one copy of a static method exists).

If you need to setup a class in such a way that you can return an instance from a static method you would need to do something similar to the following:

Public Class SampleClass

    Private Sub New()
        'Do something here
    End Sub

    Public Shared Function GetSample() As SampleClass
        Dim SampleClass As SampleClass
        SampleClass = New SampleClass

        SampleClass.Sample = "Test"

        Return SampleClass
    End Function

    Private _SampleString As String
    Public Property Sample As String
        Get
            Return _SampleString
        End Get
        Private Set(ByVal value As String)
            _SampleString = value
        End Set
    End Property

End Class

Public Class SampleClass2

    Public Sub New()
        'Here you can access the sample class in the manner you expect
        Dim Sample As SampleClass = SampleClass.GetSample
        'This would output "Test"
        Debug.Fail(Sample.Sample)
    End Sub
End Class

This method is used in various places in the CLR. Such as the System.Net.WebRequest class . where it is instantiated in this manner in usage:

' Create a request for the URL.         
        Dim request As WebRequest = WebRequest.Create("http://www.contoso.com/default.html")