รบกวนช่วยดูคำสั่ง Clear ค่าใน DatagridView ให้ Update Auto ตามที่ีารเพิ่มหรือแก้ไขข้อมูลคะ

Imports System.Data.SqlClient
Public Class frmMedicineEdit
    Dim con As New SqlConnection
    Dim cmd As New SqlCommand
    Dim strsql As String
    Dim dt As New DataTable   ' แสดงข้อมูลของ dgvMedicine
    Dim dtAdapter As SqlDataAdapter

    Private Sub frmMedicineEdit_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'con.ConnectionString = "Data Source=localhost; Initial Catalog = Safety; Integrated Security= true"
        con.ConnectionString = ("user id = sa;data source = 192.168.5.200 ; persist security info = True;initial catalog = Safety ;password = ttcadmin")
        cmd.Connection = con
        cmd.Connection = con
        con.Open()
    End Sub

    Sub Medicine()
        strsql = " select * From Medicine Order by Med_id ASC "
        dtAdapter = New SqlDataAdapter(strsql, con)
        dtAdapter.Fill(dt)
        frmMedicine.dgvMedicine.DataSource = dt

        With frmMedicine.dgvMedicine
            .AllowUserToAddRows = False
            .BorderStyle = BorderStyle.None
            .Columns(0).HeaderText = "รหัสยา"
            .Columns(1).HeaderText = "ประเภทยา"
            .Columns(2).HeaderText = "ชื่อยา"
            .Columns(3).HeaderText = "ราคา/หน่วย"
            .Columns(4).HeaderText = "หน่วย"
            .Columns(5).HeaderText = "จำนวน"
            .Columns(2).Width = "200"
            .Columns(3).Width = "80"

            .Columns(3).AutoSizeMode = DataGridViewAutoSizeColumnMode.Fill
            .AlternatingRowsDefaultCellStyle.BackColor = Color.Beige    'กำหนดตารางสลับสี
        End With
    End Sub

    Private Sub btnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click
        strsql = "UPDATE Medicine SET Med_type = '" & (cbxMed_type.Text) & "'  , Med_name = '" & (txtMed_Name.Text) & "', Med_unit = '" & (cbxMed_unit.Text) & "' Where Med_id = '" & txtMed_id.Text & "' "

        With cmd
            .Connection = con
            .CommandText = strsql
            .CommandType = CommandType.Text
            .ExecuteNonQuery()
            MessageBox.Show("แก้ไขข้อมูลเสร็จเรียบร้อย", "แก้ไขข้อมูลยา", MessageBoxButtons.OK, MessageBoxIcon.Information)

        End With
        frmMedicine.dgvMedicine.DataSource.clear()
        Medicine()

    End Sub

    Private Sub btnCancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCancel.Click
        Me.Close()
    End Sub
End Class