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我从文本框继承了自定义控件我添加了一个自定义属性，如下所示

Dim _MyVal As Object
Public Property MyVal As Object
    Get
        Return _MyVal
    End Get
    Set(value As Object)
        _MyVal = value
        If IsNothing(value) OrElse IsDBNull(value) Then
            Me.Text = "Null"
        Else
            Select Case _MyVal
                Case 1
                    Me.Text = "NewYork"
                Case 2
                    Me.Text = "London"
                Case 3
                    Me.Text = "Zwara"
                Case Else
                    Me.Text = "Unknown"
            End Select
        End If
    End Set
End Property

所以我用 DataGridView 和自定义文本框将这个属性绑定到简单 WinForm 中的 DataTable 字段，如下所示

Public Class Form10

Dim dtMain As New DataTable
Dim bsMain As New BindingSource

Private Sub Form10_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load

    dtMain.Columns.Add("Name", GetType(String))
    dtMain.Columns.Add("CityID", GetType(Integer))

    dtMain.Rows.Add("John", 1)
    dtMain.Rows.Add("Steve", 2)
    dtMain.Rows.Add("Sara", 3)
    dtMain.Rows.Add("Joe", DBNull.Value)

    bsMain.DataSource = dtMain
    dgv.DataSource = bsMain

    txtCity.DataBindings.Add(New System.Windows.Forms.Binding("MyVal", bsMain, "CityID", False, DataSourceUpdateMode.OnPropertyChanged))

    dtMain.AcceptChanges()
End Sub

我的问题是，当我浏览项目时，DataTable 发生了变化。为什么会这样？

当我将该字段绑定到 ComboBoxSelectedValue属性时，它可以完美运行。它不会通过导航改变来源；当我更改SelectedValue属性时它会改变

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