Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        DslisT11.Clear()
        OleDbDataAdapter1.Fill(DslisT11, "通信录") 'ERROR -->Fill: SelectCommand.Connection 属性尚未初始化

    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Me.BindingContext(DslisT11, "通信录").Position -= 1
        showp()
    End Sub

    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        Me.BindingContext(DslisT11, "通信录").Position += 1
        showp()
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        TextBox2.Text = Me.Name

    End Sub
    Private Sub showp()
        Dim iCnt As Integer
        Dim iPos As Integer
        iCnt = Me.BindingContext(DslisT11, "通信录").Count
        If iCnt = 0 Then
            TextBox2.Text = "(No records)"
        Else
            iPos = Me.BindingContext(DslisT11, "通信录").Position + 1
            TextBox2.Text = iPos.ToString & " of " & iCnt.ToString
        End If

    End Sub

    Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
        OleDbDataAdapter1.SelectCommand = New OleDb.OleDbCommand("select top 5 * from 通信录", OleDbConnection1)
        DslisT11.Clear()
        OleDbDataAdapter1.Fill(DslisT11, "通信录")
    End Sub
End Class

Dim mySelectText As String = "SELECT CustomerID, CompanyName FROM CUSTOMERS"

Dim myConnString As String = "Provider=SQLOLEDB;Data Source=localhost;Integrated Security=SSPI;Initial Catalog=northwind"

Dim custDA As OleDbDataAdapter = New OleDbDataAdapter(mySelectText, myConnString)

Solution: add the command string for OleDbDataAdapter1

 Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        TextBox2.Text = Me.Name
        OleDbDataAdapter1 = New OleDb.OleDbDataAdapter("select * from 通信录", OleDbConnection1)
    End Sub

[FINISH]