ใช้ ms sql 2008 กับ vb2008 ค่ะ มันต้องแก้ errorยังไง แล้วมันคืออะไร รบกวนช่วยอธิบายหน่อย ขอบคุณค่ะ

With conn
            If .State = ConnectionState.Open Then .Close()
            .ConnectionString = strConn                                             
            .Open()
End With

Imports System.Data
Imports System.Data.SqlClient

'Module Module1
'Friend strConn As String = "Data Source=PRIKII;" & "Initial Catalog=Books;Integrated Security=True"
'End Module

Public Class FormCustomers
    Dim strConn As String = "Data Source=prikii;" & "Initial Catalog=Books;Integrated Security=True"
    Dim Conn As SqlConnection = New System.Data.SqlClient.SqlConnection()
    Dim ds As DataSet = New DataSet()
    Dim cmd As SqlCommand = New SqlCommand()
    Dim rowCount As Integer = 0
    Dim positionn As Integer = 0

    Private Sub FormCustomers_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) _
    Handles MyBase.Load
        With Conn
            If .State = ConnectionState.Open Then
                .Close()
                .ConnectionString = strConn
                .Open()
            End If
        End With
        ReadData()
        FillListBox()
        Bindings()
    End Sub

    Private Sub FormCustomers_FormClosed(ByVal sender As System.Object, ByVal e As System.EventArgs) _
    Handles MyBase.FormClosed
        Conn.Close()
    End Sub

    Private Sub frmCustomer_Disposed(ByVal sender As Object, ByVal e As System.EventArgs) _
    Handles Me.Disposed
        If Conn.State = ConnectionState.Open Then Conn.Close()
    End Sub

    Private Sub ReadData()
        Dim sql As String = "SELECT * FROM Customer"
        'cmd = New SqlCommand(sql, Conn)
        Dim adapter As New SqlDataAdapter(sql, Conn)
        'adapter = New SqlDataAdapter(cmd)
        ds = New DataSet()
        adapter.Fill(ds, "cust")
        rowCount = ds.Tables("cust").Rows.Count
    End Sub

    Private Sub FillListBox()
        Dim custname As String = ""
        ListBox1.Items.Clear()
        For i = 0 To ds.Tables("cust").Rows.Count - 1
            custname = ds.Tables("cust").Rows(i)("CustomerName")
            ListBox1.Items.Add(custname)
        Next
        If (ListBox1.Items.Count > 0) Then
            ListBox1.SelectedIndex = 0
        End If
    End Sub

    Private Sub Bindings()
        TbxID.DataBindings.Add("Text", ds, "cust.CustomerID")
        TbxName.DataBindings.Add("Text", ds, "cust.CustomerName")
        TbxAdrs.DataBindings.Add("Text", ds, "cust.Address")
        TbxTel.DataBindings.Add("Text", ds, "cust.Telephone")
        TbxBirth.DataBindings.Add("Text", ds, "cust.Birthday")
    End Sub

    Private Sub ListBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) _
    Handles ListBox1.SelectedIndexChanged
        Dim index As Integer = ListBox1.SelectedIndex
        Me.BindingContext(ds, "cust").Position = index
        positionn = index
        UpdateStatus()
    End Sub

    Private Sub UpdateStatus()
        ToolStripStatusLabel1.Text = (positionn + 1) & " of " & rowCount
    End Sub

    Private Sub TabControl1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) _
    Handles TabControl1.SelectedIndexChanged
        If (TabControl1.SelectedIndex = 1) Then
            ClearBindings()
            BtnDelete.Enabled = False
            BtnSave.Enabled = False
        ElseIf (TabControl1.SelectedIndex = 0) Then
            ReadData()
            If (rowCount = 0) Then
                Return
            End If
            Bindings()
            BtnDelete.Enabled = True
            ListBox1.Enabled = True
            ListBox1.SetSelected(0, True)
        End If
    End Sub

    Private Sub ClearBindings()
        For Each c As Object In GroupBox1.Controls
            If (TypeOf c Is TextBox) Then
                c.Text = ""
                c.DataBindings.Clear()
            End If
        Next
    End Sub

    Private Sub BtnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) _
    Handles BtnSave.Click
        If (TbxName.Text = "" Or TbxAdrs.Text = "" Or TbxTel.Text = "" Or TbxBirth.Text = "") Then
            MsgBox("กรุณาใส่ข้อมูลให้ครบ !")
            Return
        End If
        Dim sql As String = ""
        If (TbxID.Text = "") Then
            sql = "INSERT INTO Customer("
            sql &= "CustomerName, Address ,Telephone, Birthday) "
            sql &= "VALUES(@nm, @adrs, @tel, @birth)"
        Else
            sql = "UPDATE Customer SET "
            sql &= "CustomerName = @nm, Address = @adrs, Telephone = @tel, Birthday = @birth "
            sql &= "WHERE CustomerID = " & TbxID.Text
        End If
        cmd = New SqlCommand(sql, Conn)
        cmd.Parameters.AddWithValue("nm", TbxName.Text)
        cmd.Parameters.AddWithValue("adrs", TbxAdrs.Text)
        cmd.Parameters.AddWithValue("tel", TbxTel.Text)
        cmd.Parameters.AddWithValue("birth", TbxBirth.Text)
        Dim affectedRow As Integer = cmd.ExecuteNonQuery()
        If (affectedRow < 1) Then
            ToolStripStatusLabel1.Text = "เกิดข้อผิดพลาดในการบันทึกข้อมูล"
        Else
            ToolStripStatusLabel1.Text = "ข้อมูลถูกจัดเก็บแล้ว"
            Dim name As String = TbxName.Text
            ReadData()
            FillListBox()
            ClearBindings()
            If (TabControl1.SelectedIndex = 0) Then
                Bindings()
            End If
            Dim idx As Integer = ListBox1.FindStringExact(name)
            If (idx > -1) Then
                ListBox1.SetSelected(idx, True)
            End If
            UpdateStatus()
        End If
    End Sub

    Private Sub BtnDelete_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnDelete.Click
        If (TbxID.Text = "") Then
            Return
        End If
        If (MsgBox("ต้องการลบข้อมูล ?", MsgBoxStyle.OkCancel) = MsgBoxResult.Cancel) Then
            Return
        End If
        Dim sql As String
        sql = "DELETE * FROM Order"
        sql &= "WHERE CustomerName = @cust"
        cmd = New SqlCommand(sql, Conn)
        Dim r As Integer = cmd.ExecuteNonQuery()
        If (r > 0) Then
            ToolStripStatusLabel1.Text = "ข้อมูลถูกลบแล้ว"
        End If
        Dim idx0 As Integer = ListBox1.SelectedIndex
        ClearBindings()
        ReadData()
        FillListBox()
        Bindings()
        If (idx0 > 0) Then
            ListBox1.SetSelected(idx0 - 1, True)
        End If
        sql = "DELETE * FROM Order WHERE CustomerName = @cust"
        cmd = New SqlCommand(sql, Conn)
        cmd.Parameters.AddWithValue("cust", TbxName.Text)
        cmd.ExecuteNonQuery()
    End Sub
End Class

With Conn
If .State = ConnectionState.Open Then
   .Close()
   .ConnectionString = strConn
    .Open()
End If
End With

With Conn
     If .State=Connection.Open Then .Close
     .ConnectionString = strConn
     .Open
End With