VB.NET ช่วยด้วยค่ะ.........ปุ่มแก้ไขไม่ทำงานอ่ะค่ะ บันทึกได้อย่างเดียว

Imports System.Data.SqlClient
Public Class frmProduct
    Dim conn As SqlConnection
    Dim com As SqlCommand
    Dim ap As SqlDataAdapter
    Dim ds As New DataSet()
    Dim dt As New DataTable
    Dim dr As SqlDataReader
    Dim s As Integer = 0
    Private Sub frmProduct_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        conn = New SqlConnection()
        With conn
            If .State = ConnectionState.Open Then .Close()
            .ConnectionString = Database.strConn.ToString
            .Open()
        End With
        Dim sql2 As String = "SELECT ชื่อประเภทสินค้า FROM ประเภทสินค้า"
        com = New SqlCommand
        With com
            .CommandType = CommandType.Text
            .CommandText = sql2
            .Connection = conn
            .Parameters.Clear()
            dr = .ExecuteReader()
            If dr.HasRows Then
                dt = New DataTable
                dt.Load(dr)
                Dim i As Integer = 0
                While (i < dt.Rows.Count)
                    C2.Items.Add(dt.Rows(i).Item("ชื่อประเภทสินค้า").ToString)
                    i += 1
                End While
                conn.Close()
            Else
                conn.Close()
                dr.Close()
            End If
        End With
        ShowData()
    End Sub
    Private Sub ShowData()
        With conn
            If .State = ConnectionState.Open Then .Close()
            .Open()
        End With
        ds.Clear()
        Dim sql As String = "Select * From สินค้า Order by รหัสสินค้า"
        com = New SqlCommand(sql, conn)
        ap = New SqlDataAdapter(com)
        ap.Fill(ds, "สินค้า")
        DataGridView1.DataSource = ds.Tables("สินค้า")
        DataGridView1.Columns.Item(0).Width = 120
        DataGridView1.Columns.Item(1).Width = 120
        DataGridView1.Columns.Item(2).Width = 120
        DataGridView1.Columns.Item(3).Width = 120
        DataGridView1.Columns.Item(4).Width = 125
        DataGridView1.Columns.Item(5).Width = 125

        conn.Close()
    End Sub
    Private Sub B1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        If T1.Text = "" Or T2.Text = "" Or T3.Text = "" Or T4.Text = "" Or C1.Text = "" Or C2.Text = "" Then
            MessageBox.Show("กรุณากรอกข้อมูลให้ครบทุกช่องด้วย", "การตรวจสอบ", MessageBoxButtons.OK, MessageBoxIcon.Warning)
        Else
            If (s = 0) Then
                With conn
                    If .State = ConnectionState.Open Then .Close()
                    .Open()
                End With

                Dim SQL1 As String = "INSERT INTO สินค้า(รหัสสินค้า,ชื่อสินค้า,จำนวน,หน่วยนับ,ราคาต่อหน่วย,ประเภทสินค้า) VALUES('" & T1.Text & "','" & T2.Text & "','" & CInt(T3.Text.Trim) & "','" & C1.Text & "','" & CDec(T4.Text.Trim) & "','" & C2.Text & "')"
                com = New SqlCommand(SQL1, conn)
                com.ExecuteNonQuery()
                conn.Close()
                Clear2()
                T1.Text = ""
                T1.Focus()
                ShowData()
            ElseIf (s = 1) Then
                With conn
                    If .State = ConnectionState.Open Then .Close()
                    .Open()
                End With

                Dim sql As String = "UPDATE สินค้า  SET ชื่อสินค้า ='" & T2.Text.Trim & "',จำนวน = '" & T3.Text.Trim & "',หน่วยนับ = '" & C1.Text.Trim & "',ราคาต่อหน่วย = '" & T4.Text.Trim & "',ประเภทสินค้า = '" & C2.Text.Trim & "' Where (รหัสสินค้า='" & T1.Text.Trim & "')"
                com = New SqlCommand(sql, conn)
                Dim a As Integer = com.ExecuteNonQuery
                If a < 1 Then
                Else
                    conn.Close()
                    ShowData()
                    Clear2()
                    T1.Text = ""
                    T1.Focus()
                    s = 0
                End If
            End If
        End If
    End Sub

    Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button5.Click
        C2.Items.Clear()
        Clear2()
        frmMain.Show()
        Me.Close()
    End Sub

    Private Sub T1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles T1.TextChanged
        With conn
            If .State = ConnectionState.Open Then .Close()
            .Open()
        End With
        Try
            Dim ac As String = "SELECT * FROM สินค้า where รหัสสินค้า='" & T1.Text.Trim & "'"
            com = New SqlCommand
            With com
                .CommandType = CommandType.Text
                .CommandText = ac
                .Connection = conn
                .Parameters.Clear()
                .Parameters.Add("สินค้า", SqlDbType.VarChar).Value = T1.Text.Trim
                dr = .ExecuteReader()
                If dr.HasRows Then
                    dt = New DataTable
                    dt.Load(dr)
                    T2.Text = dt.Rows(0).Item("ชื่อสินค้า").ToString
                    T3.Text = dt.Rows(0).Item("จำนวน").ToString
                    C1.Text = dt.Rows(0).Item("หน่วยนับ").ToString
                    T4.Text = dt.Rows(0).Item("ราคาต่อหน่วย").ToString
                    C2.Text = dt.Rows(0).Item("ประเภทสินค้า").ToString              
                    dr.Close()
                    conn.Close()
                    T2.ReadOnly = True
                    T3.ReadOnly = True
                    T4.ReadOnly = True
                    C2.Enabled = False
                    C1.Enabled = False
                    B2.Enabled = True
                    B3.Enabled = True
                    Button1.Enabled = False
                Else
                    Clear2()
                End If
            End With
        Catch ex As Exception

        End Try
    End Sub
    Private Sub Clear2()
        T2.Text = ""
        T3.Text = ""
        T4.Text = ""
        C1.Text = ""
        C2.Text = ""
        C2.SelectedIndex = -1
        C1.SelectedIndex = -1
        T2.ReadOnly = False
        T3.ReadOnly = False
        T4.ReadOnly = False
        C2.Enabled = True
        C1.Enabled = True
      
        B2.Enabled = False
        B3.Enabled = False
        Button1.Enabled = True
    End Sub

    Private Sub B2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles B2.Click

        If (T1.Text <> "") Then
            conn.Open()
            Dim s As String = "DELETE FROM สินค้า  WHERE รหัสสินค้า ='" & T1.Text.Trim & "'"
            com = New SqlCommand(s, conn)
            com.ExecuteNonQuery()
            conn.Close()
            ShowData()
            T1.Text = ""
            T1.Focus()
            Clear2()
            MessageBox.Show("ลบรายการเสร็จเรียบร้อย", "การดำเนินงาน", MessageBoxButtons.OK, MessageBoxIcon.Information)
        Else
        End If

    End Sub

    Private Sub B3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles B3.Click

        Try
            If T1.Text = "" Or T1.Text = "" Or T2.Text = "" Or T3.Text = "" Or C1.Text = "" Or T4.Text = "" Or C2.Text = "" Then
                MessageBox.Show("กรุณากรอกข้อมูลให้ครบทุกช่องด้วยค่ะ", "การตรวจสอบ", MessageBoxButtons.OK, MessageBoxIcon.Warning)
            Else
                conn.Open()
                Dim sql As String = "UPDATE สินค้า SET ชื่อสินค้า= '" & T2.Text.Trim & "',จำนวน = '" & T3.Text.Trim & "',หน่วยนับ = '" & C1.Text.Trim & "',ราคาต่อหน่วย = '" & T4.Text.Trim & "',ประเภทสินค้า ='" & C2.Text.Trim & "' Where (รหัสพนักงาน='" & T1.Text.Trim & "')"
                com = New SqlCommand(sql, conn)
                Dim a As Integer = com.ExecuteNonQuery
                If a < 1 Then
                    conn.Close()
                    MessageBox.Show("ชื่อสินค้านี้มีแล้ว", "การตรวจสอบ", MessageBoxButtons.OK, MessageBoxIcon.Warning)
                    T1.Text = ""
                    T1.Focus()
                Else
                    conn.Close()
                    MessageBox.Show("ข้อมูลถูกจัดเก็บแล้ว", "การตรวจสอบ", MessageBoxButtons.OK, MessageBoxIcon.Information)
                    ShowData()
                    Clear()
                End If
            End If
        Catch ex As Exception
        End Try

        T2.ReadOnly = True
        T3.ReadOnly = True
        T4.ReadOnly = True
        C2.Enabled = True
        C1.Enabled = True
        B2.Enabled = True
        Button1.Enabled = True
        s = 1
    End Sub

    Private Sub GroupBox1_Enter(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles GroupBox1.Enter

    End Sub

    Private Sub DataGridView1_CellContentClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellContentClick

    End Sub

    Private Sub T3_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles T3.TextChanged

    End Sub

    Private Sub Clear()
        Throw New NotImplementedException
    End Sub

    Private Sub D1_ValueChanged(ByVal sender As System.Object, ByVal e As System.EventArgs)

    End Sub
End Class