Question

注意：这个问题不是询问如何传递类的实例。它询问如何传递具有共享项的类。

例如...... 关于如何制作能够做到这一点的功能的任何想法？

Public Function InsertSQL(ByVal xClass As Type) As String
    InsertSQL = "Insert into "
    InsertSQL = InsertSQL & xClass.TableName
    InsertSQL = InsertSQL & " ("
    InsertSQL = InsertSQL & xClass.FieldList
    InsertSQL = InsertSQL & " )"
End Function

使用这样的一组类：

Public Class cClient
    Public Shared TableName = "Clients"
    Public Shared Function FieldList() As String
        FieldList = "Name, Phone"
    End Function
End Class

Public Class cSale
    Public Shared TableName = "Sales"
    Public Shared Function FieldList() As String
        FieldList = "Name, Amount"
    End Function
End Class

我在Google上搜索了“如何将一个类作为参数传递”，但是没有找到任何解决方法来访问该类的共享方法。我只能得到认为我想传递该类实例的结果。

请注意，此代码只是一个示例。而且 - 当然，如果我传递一个类的实例，我没有问题但是 - 这不是我想弄清楚的。

Answer 1

我会在你的情况下使用Inheritance。像这样的东西

Public Sub Main
    Dim c = new cClient()
    Dim sql = InsertSQL(c)
    Console.WriteLine(sql)
End Sub


' Pass an actual instance of a class that inehrits cTableBase'
' all of these classes have the same BASE functions and property
' defined in the base class
Public Function InsertSQL(ByVal xClass As cTableBase) As String
    InsertSQL = "Insert into "
    InsertSQL = InsertSQL & xClass.TableName
    InsertSQL = InsertSQL & " ("
    InsertSQL = InsertSQL & xClass.FieldList
    InsertSQL = InsertSQL & " )"
End Function

Public Class cTableBase
    Public TableName As String 
    Public Overridable Function FieldList() As String
    End Function
End Class

Public Class cClient 
    Inherits cTableBase
    Public Sub New
        TableName = "Clients"
    End Sub
    Public Overrides Function FieldList() As String
        FieldList = "Name, Phone"
    End Function
End Class

Public Class cSale 
    Inherits cTableBase
    Public Sub New
        TableName = "Sales"
    End Sub
    Public Overrides Function FieldList() As String
        FieldList = "Name, Amount"
    End Function
End Class

正如您在下面的评论中发表的那样。这可以使用传递给InsertSQL的方法使用反射

来完成

Sub Main
    Dim c = new cClient()
    Dim result = InsertSQL(c.GetType())
    Console.WriteLine(result)
End Sub

Public Function InsertSQL(ByVal xClass As Type) As String

    Dim fi = xClass.GetField("TableName")
    Dim tableName = fi.GetValue(xClass)

    Dim mi = xClass.GetMethod("FieldList")
    Dim fieldList = mi.Invoke(xClass, Nothing)

    InsertSQL = "Insert into "
    InsertSQL = InsertSQL & tableName
    InsertSQL = InsertSQL & " ("
    InsertSQL = InsertSQL & fieldList
    InsertSQL = InsertSQL & " )"
End Function

如何将类作为参数传递，然后使用该类的共享方法？

1 个答案: