Question

我正在使用集合和结构在类中存储一些已解析的数据，但是当我尝试检索数据时，它是null。在form1上，我可以获得响应字符串，这是所有原始数据。我是否正确地将解析后的数据添加到集合中？我是否正确地在form1上调用它？

Private Sub btnStart_Click(sender As System.Object, e As System.EventArgs) Handles btnStart.Click
    Dim dloader as new Downloader(blah)
 'this does not work
    Dim test as new _ListInfo
      msgbox(test.Name) ' produces an empty message box
'this works
     msgbox(dloader.Download)
End Sub

这是我的课程代码：

Public Structure _Info
  Dim Name As String
End Structure

Public Class Downloader
  Dim _ListCollection As New Collection(Of _ListInfo)

Public ReadOnly Property ListCollection() As Collection(Of _ListInfo)
    Get
        ListCollection = _ListCollection
    End Get
End Property

Public Function Download() As String
  'doing the download
  ParseList()
  Return _ResponseString
End Function    

Private Sub ParseList()
    _ListCollection.Clear()
 Dim Name As String
 Dim MyInfo As _ListInfo
   MyInfo.Name = Name
    _ListCollection.Add(MyInfo)
End Sub

Answer 1

为什么你期望它能起作用？您只是在新建一个结构并访问一个属性。你不想做这样的事情：

Dim dloader as new Downloader(blah)
dloader.Download()
' Show first name.
MsgBox(dloader.ListCollection(0).Name)

从公共结构和集合中检索数据

1 个答案: