继承通用类 [英] Inherit Generic Class

问题描述

通用父类为:

The generic parent Class is:

Option Strict Off
Option Explicit On

Imports System

Public MustInherit Class CNew_DataFile(Of T As Structure)
    Private jRecord As Type
End Class

子类是:

The child class is:

Option Strict Off
Option Explicit On

Public Class CTest_ProdUnit

    Inherits CNew_DataFile(Of RecordType)

    Private Structure RecordType
        Dim Index As Integer
        Dim SubUnit As Integer      ' reference to the sub unit index
        <VBFixedString(150)> Dim Name As String
        <VBFixedString(256)> Dim Description As String
        <VBFixedString(8)> Dim Abbr As String    ' abbreviation
        Dim InvoiceUnitType As Short    ' the unit type printed on the invoice
        Dim UnitType As Short       ' the type of unit (base, product, or both)
        Dim Activity As Short
        Dim SubUnitQty As Single
        Dim MeasSystem As Short     ' the measurement system
    End Structure

End Class

Visual Studio报告以下错误:''CTest_ProdUnit"不能从类"CNew_DataFile(Of RecordType)"继承，因为它会将类型"RecordType"的访问扩展到名称空间"WareHouseMngtSys". >
显然，该项目的名称是WareHouseMngtSys.

Visual Studio reports the following error: " ''CTest_ProdUnit'' cannot inherit from class ''CNew_DataFile(Of RecordType)'' because it expands the access of type ''RecordType'' to namespace ''WareHouseMngtSys''. "

Obviously, the name of the project is WareHouseMngtSys.

推荐答案

好的，这很明显.

您的RecordType结构在CTest_ProdUnit类内部被声明为私有.这意味着该结构仅在CNew_DataFile类内部可见.

但是，由于它继承自CNew_DataFile( Of RecordType )，因此RecordType可见性与Public accessibility修饰符冲突.

解决方案很简单.在其所在的类的外部声明RecordType并将其公开.

OK, it''s fairly obvious.

Your RecordType structure is declared private inside the CTest_ProdUnit class. That means the struct will be visible only inside the CNew_DataFile class.

But, since it''s inheriting from CNew_DataFile(Of RecordType) the RecordType visibility is in conflict with Public accessibility modifier.

The solution is easy. Declare RecordType outside the Class it''s sitting in and make it Public.

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