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您不会这么认为，但是当列表框绑定到数据源时（据我所知），它确实如此。

我已将行为简化为下面的代码。“if”行在通过数据绑定加载列表和“手动”加载列表之间切换（两者都使用相同的数据表）。在每种情况下，我都会在之后设置选定的索引，然后更改父表单。手动加载时，选定的索引会保留，绑定时会丢失。我看不出这有什么意义——我不明白为什么更改主机表单会改变列表的任何属性。这是一个错误吗？

Public Class Form1
    Sub main() Handles Me.Load
        Dim ListControl1 As ListBox = New ListBox
        ListControl1.Parent = Me
        Dim dt = New DataTable
        dt.Columns.Add("intColourID")
        dt.Columns.Add("strName")
        dt.Rows.Add({1, "Red"})
        dt.Rows.Add({2, "Green"})
        dt.Rows.Add({3, "Blue"})

        ListControl1.ValueMember = dt.Columns(0).ColumnName
        ListControl1.DisplayMember = dt.Columns(1).ColumnName
        If False Then
            ListControl1.DataSource = dt
        Else
            For i = 0 To dt.Rows.Count - 1
                ListControl1.Items.Add(dt.Rows(i)("strName").ToString)
            Next
        End If
        ListControl1.SelectedIndex = 2
        Dim z As Form = New Form
        ListControl1.Parent = z
        z.Show()
    End Sub
End Class
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1 回答 1

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The correct way of adding a control to a form is not to set its parent, but to add it to the Controls collection of the form. If I do it like this I do not get an exception (the three last lines commented out as you write in your comment).

Me.Controls.Add(ListControl1)   ' Instead of ListControl1.Parent = Me
于 2012-03-22T21:15:38.710 回答