vb.net - 该枚举器绑定(bind)到的列表已被修改

Question

我这里有这段代码，在下一个语句中它给了我一个错误:

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，我可以尝试。

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。该代码在代码片段中不可见。请确保发布的代码没有在工作线程中运行，这是不合法的。它确实像您在工作线程中运行的代码一样嘎嘎作响。

通用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。