สอบถามปัญหาคำสั่งเรื่อง VB ช่วยหน่อยครับ ต้องเอาไปสอบวันพรุ่งนี้ รายละเอียดอยู่ด่านในครับ VB.net

Imports System.Data.OleDb

Public Class Form1
    Dim Conn As New OleDbConnection
    Dim dc As New OleDbCommand
    Dim dr As OleDbDataReader
    Dim da As OleDbDataAdapter
    Dim ds As New DataSet
    Dim dt As DataTable
    Dim currentrecord As Integer = 0
    Dim recordcount As Integer = 0
    Dim actionflag As String = ""
    Dim IsFind As Boolean = False
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        With Conn
            If .State = ConnectionState.Open Then .Close()
            .ConnectionString = ConDB
            .Open()
        End With
        formatdatagrid()
        clearall()
        enableall()
        showdata()
    End Sub
    Sub showdata() 'การแสดงข้อมูล
        Dim sqlshow As String = ""
        sqlshow = "SELECT Employee.EmpId, Employee.EmpName, Employee.CardId, "
        sqlshow &= " Employee.Addno, Employee.Building, Employee.Moo, "
        sqlshow &= " Employee.Land, Employee.Road, Locality.LName, "
        sqlshow &= " Amphur.AName, Province.ProName, Amphur.Code, Employee.Phone"
        sqlshow &= " FROM ((Amphur INNER JOIN Employee ON Amphur.AID = Employee.AID)"
        sqlshow &= " INNER JOIN Province ON Amphur.ProID = Province.ProID) INNER JOIN "
        sqlshow &= " Locality ON (Amphur.AID = Locality.AID) AND "
        sqlshow &= " (Employee.LID = Locality.LID);"

        With dc
            .CommandType = CommandType.Text
            .CommandText = sqlshow
            .Connection = Conn
            dr = .ExecuteReader
            If dr.HasRows Then
                dt = New DataTable
                dt.Load(dr)
                DataGridView1.DataSource = dt
                formatdatagrid()
            Else
                DataGridView1.DataSource = Nothing
                formatdatagrid()
            End If
        End With
        dr.Close()
    End Sub
    Sub formatdatagrid()
        With DataGridView1
            .ReadOnly = True
            If .RowCount > 0 Then
                .Font = New Font("Ms Sans Serif", 10.0)
                .Columns(0).HeaderText = "รหัสพนักงาน"
                .Columns(1).HeaderText = "ชื่อ-นามสกุลพนักงาน"
                .Columns(2).HeaderText = "หมายเลขบัตรประชาชน"
                .Columns(3).HeaderText = "บ้านเลขที่"
                .Columns(4).HeaderText = "หมู่ที่"
                .Columns(5).HeaderText = "อาคาร/หมู่บ้าน"
                .Columns(6).HeaderText = "ซอย"
                .Columns(7).HeaderText = "ถนน"
                .Columns(8).HeaderText = "ตำบล"
                .Columns(9).HeaderText = "อำเภอ"
                .Columns(10).HeaderText = "จังหวัด"
                .Columns(11).HeaderText = "รหัสไปรษณีย์"
                .Columns(12).HeaderText = "โทรศัพท์ที่ติดต่อได้"


                .Columns(0).Width = 150
                .Columns(1).Width = 250
                .Columns(2).Width = 200
                .Columns(3).Width = 100
                .Columns(4).Width = 100
                .Columns(5).Width = 150
                .Columns(6).Width = 200
                .Columns(7).Width = 200
                .Columns(8).Width = 200
                .Columns(9).Width = 200
                .Columns(10).Width = 200
                .Columns(11).Width = 100
                .Columns(12).Width = 150
            End If
        End With
    End Sub
    Sub clearall()
        txtempid.Clear()
        txtname.Clear()
        txtcardid.Clear()
        txtaddno.Clear()
        txtmoo.Clear()
        txtbuilding.Clear()
        txtland.Clear()
        txtroad.Clear()
        combobox1.Text = "กรุณาเลือก"
        combobox2.Text = "กรุณาเลือก"
        combobox3.Text = "กรุณาเลือก"
        txtpostalcode.Text = ""
        txtphone.Text = ""
    End Sub
    Sub enableall()
        txtname.Enabled = False
        txtcardid.Enabled = False
        txtaddno.Enabled = False
        txtmoo.Enabled = False
        txtbuilding.Enabled = False
        txtland.Enabled = False
        txtroad.Enabled = False
        combobox1.Enabled = False
        combobox2.Enabled = False
        combobox3.Enabled = False
        txtpostalcode.Enabled = False
        txtphone.Enabled = False
    End Sub
   
    Sub autoid()
        Dim sqlauto As String = ""
        Dim nid As String
        Dim tauauto As Integer = 0
        sqlauto = "SELECT Top 1 EmpId FROM Employee ORDER BY EmpId DESC;"
        Try
            With dc
                .CommandType = CommandType.Text
                .CommandText = sqlauto
                .Connection = conn
                dr = .ExecuteReader
                dr.Read()
                nid = dr.Item("EmpId")
                tauauto = CInt(nid) + 1
                txtempid.Text = Format(tauauto.ToString("000000"))
            End With
        Catch ex As Exception
            txtempid.Text = "000001"

        End Try
        dr.Close()
    End Sub
    Sub showcombo()
        Dim sqlPro As String = "SELECT ProId,ProName FROM Province WHERE status='0' Order By ProId"
        da = New OleDbDataAdapter(sqlPro, Conn)
        da.Fill(ds, "Province")
        If ds.Tables("Province").Rows.Count <> 0 Then
            With combobox1
                .DataSource = ds.Tables("Province")
                .DisplayMember = "ProName"
                .ValueMember = "ProId"
            End With
        End If
    End Sub
    Private Sub combobox2_SelectionChangeCommitted(ByVal sender As Object, ByVal e As System.EventArgs) Handles combobox2.SelectionChangeCommitted

        Dim da3 As OleDbDataAdapter
        Dim ds3 As New DataSet
        ds3.Tables.Clear()

        Dim sql1 As String = "SELECT Locality.LID, Locality.LName FROM Locality INNER JOIN Amphur ON Locality.AID = Amphur.AID WHERE Amphur.status = '" & 0 & "' and Locality.AID = TextBox1.Text;"

        da3 = New OleDbDataAdapter(sql1, Conn)
        da3.Fill(ds3, "Locality")
        If ds3.Tables("Locality").Rows.Count <> 0 Then

            With combobox3
                .DataSource = ds3.Tables("Locality")
                .DisplayMember = "LName"
                .ValueMember = "LID"
            End With
        End If
    End Sub
    Private Sub btnadd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnadd.Click
        autoid() : unenableall()
        actionflag = "ADD"
        txtname.Focus()
        showcombo()
    End Sub

    Private Sub btnsave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnsave.Click
        If Not IsNumeric(txtcardid.Text) Then
            MessageBox.Show("ต้องกรอกข้อมูลเป็นตัวเลขเท่านั้น", "ตรวจสอบข้อมูล", MessageBoxButtons.OK, MessageBoxIcon.Warning)
            txtcardid.Clear() : txtcardid.Focus() : Exit Sub
        ElseIf txtcardid.TextLength < 13 Then
            MessageBox.Show("กรุณากรอกข้อมูล หมายเลขบัตรประชาชนบัตรประชาชน เป็นตัวเลข 13 หลัก", "ตรวจสอบข้อมูล", MessageBoxButtons.OK, MessageBoxIcon.Warning)
            txtcardid.Clear() : txtcardid.Focus() : Exit Sub
        End If

        Dim save As String = ""
        Dim msgb As String = ""
        Select Case actionflag
            Case "ADD"
                save = "Insert Into Employee (EmpId,EmpName,CardId,Addno,Building,Moo,Land,Road,LID,AID,ProID,Phone) "
                save &= " values ('" & txtempid.Text & "','" & txtname.Text & "','" & txtcardid.Text & "','" & txtaddno.Text & "','" & txtbuilding.Text & "',"
                save &= "'" & txtmoo.Text & "','" & txtland.Text & "','" & txtroad.Text & "',"
                save &= "'" & combobox3.SelectedValue & "','" & combobox2.SelectedValue & "','" & combobox1.SelectedValue & "','" & txtphone.Text & "')"
        End Select
        With Conn
            If .State = ConnectionState.Open Then .Close()
            .ConnectionString = ConDB
            .Open()
        End With
        If actionflag = "add." Then
            msgb = "คุณต้องการเพิ่มข้อมูลใช่หรือไม่"
        End If
        If MessageBox.Show(msgb & "บันทึกข้อมูล", "คำยืนยัน", MessageBoxButtons.YesNo, MessageBoxIcon.Question, MessageBoxDefaultButton.Button1) = Windows.Forms.DialogResult.Yes Then
            With dc
                .CommandType = CommandType.Text
                .CommandText = save
                .Connection = Conn
                .ExecuteNonQuery()
            End With
        End If
        clearall()
        showdata()
        dr.Close()
    End Sub
    Sub unenableall()
        txtname.Enabled = True : txtcardid.Enabled = True
        txtaddno.Enabled = True
        txtmoo.Enabled = True
        txtbuilding.Enabled = True
        txtland.Enabled = True
        txtroad.Enabled = True
        combobox1.Enabled = True
        combobox2.Enabled = True
        combobox3.Enabled = True
        txtphone.Enabled = True
    End Sub
    Private Sub btncancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btncancel.Click
        clearall()
        enableall()
    End Sub
    Private Sub btnexit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnexit.Click
        End
    End Sub
    Private Sub GroupBox1_Enter(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles GroupBox1.Enter

    End Sub

End Class