vb.net - 此枚举器绑定(bind)到的列表已被修改

Question

我这里有这段代码，在下一条语句中它给我一个错误:

List that this enumerator is bound to has been modified. An enumerator can only be used if the list does not change.

我真的不知道如何进一步解释这个问题，但如果你需要我可以试试。

For Each itemChecked In storedAuthorsListbox.CheckedItems
  Dim selectedAuthor As String = storedAuthorsListbox.SelectedItem.ToString()
  Dim authorFile As String = "Authors\" & itemChecked.ToString()
  Dim document As XmlReader = New XmlTextReader(authorFile)

  metaInfo &= "[Author]" & vbNewLine

  While (document.Read())
    Dim type = document.NodeType
    If (type = XmlNodeType.Element) Then
      If (document.Name = "Name") Then
        metaInfo &= "Name=" & document.ReadInnerXml.ToString() & vbNewLine
      ElseIf (document.Name = "Website") Then
        metaInfo &= "Website=" & document.ReadInnerXml.ToString() & vbNewLine
      ElseIf (document.Name = "Notes") Then
        metaInfo &= "Notes=" & document.ReadInnerXml.ToString() & vbNewLine
      End If
    End If
  End While
  document.Close()
Next

Answer 1

当您迭代它时，某处的某些代码正在更改 storedAuthorsListbox。该代码片段中不可见。请确保发布的代码未在工作线程中运行，这是不合法的。它肯定像您在 worker 中运行的那种代码一样嘎嘎作响。

一般的解决方案是制作项目的副本并从该副本而不是控件开始工作:

    Dim copy = storedAuthorsListBox.SelectedItems.OfType(Of String)().ToList()
    For Each itemchecked In copy
        '' etc..
    Next

如果它在工作线程中运行，则将副本传递给工作线程。