vb.net - 从绑定(bind)列表中获取已删除项目的索引

Question

我能够获取添加到 BindingList 的项目的索引。当我尝试获取已删除项目的索引时，出现错误

Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index

这是我的代码

Private Sub cmdRemove_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdRemove.Click

    For i As Integer = 0 To _assignedSelection.SelectedCount - 1
        Dim item As Jurisdiction = CType(_assignedSelection.GetSelectedRow(i), Jurisdiction)
        _list.Remove(item)
    Next

End Sub


Private Sub list_Change(ByVal sender As Object, ByVal e As ListChangedEventArgs) Handles _list.ListChanged

    If (_list.Count > 0) Then


        Select Case e.ListChangedType
            Case ListChangedType.ItemAdded
                _dal.InsertJurisdiction(_list.Item(e.NewIndex))
            Case ListChangedType.ItemDeleted
                'MsgBox(e.NewIndex.ToString)
                _dal.DeleteJurisdiction(_list.Item(e.NewIndex)) <--------HERE
        End Select

    End If

End Sub

编辑:也欢迎用 C# 提供答案......有人吗？

Answer 1

该项目在事件触发之前被删除。这意味着(无需额外代码)您无法找到正在删除的项目。

但是，您可以从 BindingList 继承，并重写RemoveItem:

public class BindingListWithRemoving<T> : BindingList<T>
{
    protected override void RemoveItem(int index)
    {
        if (BeforeRemove != null)
            BeforeRemove(this, 
                  new ListChangedEventArgs(ListChangedType.ItemDeleted, index));

        base.RemoveItem(index);
    }

    public event EventHandler<ListChangedEventArgs> BeforeRemove;
}

您还应该复制 BindingList 构造函数。另外，不要尝试使其可取消，因为调用者可能会认为调用 Remove 确实会删除该项目。