Visual Basic

Hi! Can somebody help me. I am beginner. I have a project and need to update datagridview with image column, using Access databse. I have code for insert new row with image and as I understand it can be modified for updating row. I try to modify, but problem is not working. Now no any alarms or errors occurs, database not changed.
Many thanks un advance.

<pre> Private Sub Btn_Save_Click(sender As Object, e As EventArgs) Handles Btn_Update.Click


        Try
            If PhotoPictureBox.Image Is Nothing Then
                If MsgBox("Are you sure you don't want to upload any pictures?", MsgBoxStyle.Information + MsgBoxStyle.YesNo, "Missing picture") Then
                    Dim CN As New OleDbConnection(connection)
                    CN.Open()

                    Dim Int As String
                    Int = "UPDATE Germany set [Year_of_release]=@year_of_release, [Denomination]=@denomination, [Governing_body]=@governing_body, [Acquired]=@acquired, [Date_of_purchase]=@date_of_purchase, [Course]=@course, [Material]=@material WHERE [ID]=@ID"


                    Dim cmd As New OleDbCommand(Int, CN)

                    'cmd.Parameters.Add("@ID", OleDbType.VarChar).Value = IDTextBox.Text
                    cmd.Parameters.Add("@year_of_release", OleDbType.VarChar).Value = Year_of_releaseDateTimePicker.Value
                    cmd.Parameters.Add("@denomination", OleDbType.VarChar).Value = DenominationTextBox.Text
                    cmd.Parameters.Add("@governing_body", OleDbType.VarChar).Value = Governing_bodyTextBox.Text
                    cmd.Parameters.Add("@acquired", OleDbType.VarChar).Value = AcquiredTextBox.Text
                    cmd.Parameters.Add("@date_of_purchase", OleDbType.VarChar).Value = Date_of_purchaseDateTimePicker.Value
                    cmd.Parameters.Add("@course", OleDbType.VarChar).Value = CourseTextBox.Text
                    cmd.Parameters.Add("@material", OleDbType.VarChar).Value = MaterialTextBox.Text

                    cmd.ExecuteNonQuery()

                    cmd.Dispose()
                    CN.Close()
                    CN.Dispose()
                End If

            Else
                If imgName <> "" Then
                    Dim fs As FileStream
                    fs = New FileStream(imgName, FileMode.Open, FileAccess.Read)

                    Dim picturebytes As Byte() = New Byte(fs.Length - 1) {}
                    fs.Read(picturebytes, 0, System.Convert.ToInt32(fs.Length))
                    fs.Close()

                    Dim CN As New OleDbConnection(connection)
                    CN.Open()

                    Dim Int As String
                    Int = "UPDATE Germany set [Year_of_release]=@year_of_release, [Denomination]=@denomination, [Governing_body]=@governing_body, [Acquired]=@acquired, [Date_of_purchase]=@date_of_purchase, [Course]=@course, [Material]=@material, [Photo]=@photo WHERE [ID]=@ID"


                    Dim imgparam As New OleDbParameter()
                    imgparam.OleDbType = OleDbType.Binary
                    imgparam.ParameterName = "@photo"
                    imgparam.Value = picturebytes

                    Dim cmd As New OleDbCommand(Int, CN)

                    cmd.Parameters.Clear()
                    cmd.Parameters.Add("@ID", OleDbType.VarChar).Value = IDTextBox.Text
                    cmd.Parameters.Add("@year_of_release", OleDbType.VarChar).Value = Year_of_releaseDateTimePicker.Value
                    cmd.Parameters.Add("@denomination", OleDbType.VarChar).Value = DenominationTextBox.Text
                    cmd.Parameters.Add("@governing_body", OleDbType.VarChar).Value = Governing_bodyTextBox.Text
                    cmd.Parameters.Add("@acquired", OleDbType.VarChar).Value = AcquiredTextBox.Text
                    cmd.Parameters.Add("@date_of_purchase", OleDbType.VarChar).Value = Date_of_purchaseDateTimePicker.Value
                    cmd.Parameters.Add("@course", OleDbType.VarChar).Value = CourseTextBox.Text
                    cmd.Parameters.Add("@material", OleDbType.VarChar).Value = MaterialTextBox.Text
                    cmd.Parameters.Add(imgparam)

                    cmd.ExecuteNonQuery()

                    cmd.Dispose()
                    CN.Close()
                    CN.Dispose()

                End If





            End If
        Catch ex As Exception
            MsgBox(ex.Message.ToString)
        End Try


    End Sub

Private Sub Btn_Save_Click(sender As Object, e As EventArgs) Handles Btn_Update.Click


       Try
           If PhotoPictureBox.Image Is Nothing Then
               If MsgBox("Are you sure you don't want to upload any pictures?", MsgBoxStyle.Information + MsgBoxStyle.YesNo, "Missing picture") Then
                   Dim CN As New OleDbConnection(connection)
                   CN.Open()

                   Dim Int As String
                   Int = "UPDATE Germany set [Year_of_release]=@year_of_release, [Denomination]=@denomination, [Governing_body]=@governing_body, [Acquired]=@acquired, [Date_of_purchase]=@date_of_purchase, [Course]=@course, [Material]=@material WHERE [ID]=@ID"


                   Dim cmd As New OleDbCommand(Int, CN)

                   'cmd.Parameters.Add("@ID", OleDbType.VarChar).Value = IDTextBox.Text
                   cmd.Parameters.Add("@year_of_release", OleDbType.VarChar).Value = Year_of_releaseDateTimePicker.Value
                   cmd.Parameters.Add("@denomination", OleDbType.VarChar).Value = DenominationTextBox.Text
                   cmd.Parameters.Add("@governing_body", OleDbType.VarChar).Value = Governing_bodyTextBox.Text
                   cmd.Parameters.Add("@acquired", OleDbType.VarChar).Value = AcquiredTextBox.Text
                   cmd.Parameters.Add("@date_of_purchase", OleDbType.VarChar).Value = Date_of_purchaseDateTimePicker.Value
                   cmd.Parameters.Add("@course", OleDbType.VarChar).Value = CourseTextBox.Text
                   cmd.Parameters.Add("@material", OleDbType.VarChar).Value = MaterialTextBox.Text

                   cmd.ExecuteNonQuery()

                   cmd.Dispose()
                   CN.Close()
                   CN.Dispose()
               End If

           Else
               If imgName <> "" Then
                   Dim fs As FileStream
                   fs = New FileStream(imgName, FileMode.Open, FileAccess.Read)

                   Dim picturebytes As Byte() = New Byte(fs.Length - 1) {}
                   fs.Read(picturebytes, 0, System.Convert.ToInt32(fs.Length))
                   fs.Close()

                   Dim CN As New OleDbConnection(connection)
                   CN.Open()

                   Dim Int As String
                   Int = "UPDATE Germany set [Year_of_release]=@year_of_release, [Denomination]=@denomination, [Governing_body]=@governing_body, [Acquired]=@acquired, [Date_of_purchase]=@date_of_purchase, [Course]=@course, [Material]=@material, [Photo]=@photo WHERE [ID]=@ID"


                   Dim imgparam As New OleDbParameter()
                   imgparam.OleDbType = OleDbType.Binary
                   imgparam.ParameterName = "@photo"
                   imgparam.Value = picturebytes

                   Dim cmd As New OleDbCommand(Int, CN)

                   cmd.Parameters.Clear()
                   cmd.Parameters.Add("@ID", OleDbType.VarChar).Value = IDTextBox.Text
                   cmd.Parameters.Add("@year_of_release", OleDbType.VarChar).Value = Year_of_releaseDateTimePicker.Value
                   cmd.Parameters.Add("@denomination", OleDbType.VarChar).Value = DenominationTextBox.Text
                   cmd.Parameters.Add("@governing_body", OleDbType.VarChar).Value = Governing_bodyTextBox.Text
                   cmd.Parameters.Add("@acquired", OleDbType.VarChar).Value = AcquiredTextBox.Text
                   cmd.Parameters.Add("@date_of_purchase", OleDbType.VarChar).Value = Date_of_purchaseDateTimePicker.Value
                   cmd.Parameters.Add("@course", OleDbType.VarChar).Value = CourseTextBox.Text
                   cmd.Parameters.Add("@material", OleDbType.VarChar).Value = MaterialTextBox.Text
                   cmd.Parameters.Add(imgparam)

                   cmd.ExecuteNonQuery()

                   cmd.Dispose()
                   CN.Close()
                   CN.Dispose()

               End If





           End If
       Catch ex As Exception
           MsgBox(ex.Message.ToString)
       End Try


   End Sub

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Operator '=' is not defined for type for 'DBNull' and string '1'.

Dim cnn = New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + str_Database + ";Extended Properties=Excel 12.0;")
        Dim cmd = New OleDbCommand()
        Dim str_SQL As String = ""
        Dim int_Max_SN As Integer

        Try
            If (tb_SN.Text = "") Then
                cnn.Open()
                cmd.Connection = cnn
                cmd.CommandType = CommandType.Text
                cmd.CommandText = "SELECT IIF(ISNULL(MAX(VAL([S/N]))), 0, MAX(VAL([S/N]))) FROM [Sheet2$]"
                int_Max_SN = cmd.ExecuteScalar()
                cnn.Close()

                tb_SN.Text = int_Max_SN + 1

                str_SQL += "INSERT INTO [Sheet2$] "
                str_SQL += "([S/N], [MPN], [Description], [OEM (Manufacturer)], [MTBF (Hours)], [Failure Rate], [Repair Turn Around Time], [Utilization Rate], [Population], [Spares Required], [Testing], [Price Per Unit], [Total Cost Per Line Item]) "
                str_SQL += "VALUES (" + tb_SN.Text + ", "
                str_SQL += "'" + tb_MPN.Text + "', "
                str_SQL += "'" + tb_Description.Text + "', "
                str_SQL += "'" + tb_OEM.Text + "', "
                If (IsNumeric(tb_MTBF.Text)) Then str_SQL += tb_MTBF.Text + ", " Else str_SQL += "null, "
                If (IsNumeric(tb_Failure_Rate.Text)) Then str_SQL += tb_Failure_Rate.Text + ", " Else str_SQL += "null, "
                If (IsNumeric(tb_Year_Of_Support.Text)) Then str_SQL += tb_Year_Of_Support.Text + ", " Else str_SQL += "null, "
                If (IsNumeric(tb_Utilization_Rate.Text)) Then str_SQL += tb_Utilization_Rate.Text + ", " Else str_SQL += "null, "
                If (IsNumeric(tb_Population.Text)) Then str_SQL += tb_Population.Text + ", " Else str_SQL += "null, "
                If (IsNumeric(tb_Spares_Required.Text)) Then str_SQL += tb_Spares_Required.Text + ", " Else str_SQL += "null, "
                If (IsNumeric(tb_Price_Per_Unit.Text)) Then str_SQL += tb_Price_Per_Unit.Text + ", " Else str_SQL += "null, "
                If (IsNumeric(tb_Total_Cost_Per_Line_Item.Text)) Then str_SQL += tb_Total_Cost_Per_Line_Item.Text + ", " Else str_SQL += "null, "
                If (IsNumeric(tb_Total_Uptime.Text)) Then str_SQL += tb_Total_Uptime.Text Else str_SQL += "null "
                str_SQL += ")"

                cnn.Open()
                cmd.Connection = cnn
                cmd.CommandType = CommandType.Text
                cmd.CommandText = str_SQL
                cmd.ExecuteNonQuery()
                cnn.Close()

                LoadRecords()

                MessageBox.Show("New record has been added successfully!!", "", MessageBoxButtons.OK, MessageBoxIcon.Information)
            Else
                For int_Row_Index As Integer = 0 To dgv_Excel.Rows.Count - 1
                    If (dgv_Excel.Rows(int_Row_Index).Cells(0).Value = tb_SN.Text) Then
                        dgv_Excel.Rows(int_Row_Index).Cells(1).Value = tb_MPN.Text
                        dgv_Excel.Rows(int_Row_Index).Cells(2).Value = tb_Description.Text
                        dgv_Excel.Rows(int_Row_Index).Cells(3).Value = tb_OEM.Text

                        dgv_Excel.Rows(int_Row_Index).Cells(4).Value = IIf(IsNumeric(tb_MTBF.Text), tb_MTBF.Text, DBNull.Value)
                        dgv_Excel.Rows(int_Row_Index).Cells(5).Value = IIf(IsNumeric(tb_Failure_Rate.Text), tb_Failure_Rate.Text, DBNull.Value)
                        dgv_Excel.Rows(int_Row_Index).Cells(6).Value = IIf(IsNumeric(tb_Year_Of_Support.Text), tb_Year_Of_Support.Text, DBNull.Value)
                        dgv_Excel.Rows(int_Row_Index).Cells(7).Value = IIf(IsNumeric(tb_Utilization_Rate.Text), tb_Utilization_Rate.Text, DBNull.Value)
                        dgv_Excel.Rows(int_Row_Index).Cells(8).Value = IIf(IsNumeric(tb_Population.Text), tb_Population.Text, DBNull.Value)
                        dgv_Excel.Rows(int_Row_Index).Cells(9).Value = IIf(IsNumeric(tb_Spares_Required.Text), tb_Spares_Required.Text, DBNull.Value)
                        dgv_Excel.Rows(int_Row_Index).Cells(10).Value = IIf(IsNumeric(tb_Price_Per_Unit.Text), tb_Price_Per_Unit.Text, DBNull.Value)
                        dgv_Excel.Rows(int_Row_Index).Cells(11).Value = IIf(IsNumeric(tb_Total_Cost_Per_Line_Item.Text), tb_Total_Cost_Per_Line_Item.Text, DBNull.Value)
                        dgv_Excel.Rows(int_Row_Index).Cells(12).Value = IIf(IsNumeric(tb_Total_Uptime.Text), tb_Total_Uptime.Text, DBNull.Value)

                        int_Row_Index += 1
                    End If
                Next

                str_SQL += "UPDATE [Sheet2$] "
                str_SQL += "SET [MPN] = '" + tb_MPN.Text + "', "
                str_SQL += "[Description] = '" + tb_Description.Text + "', "
                str_SQL += "[OEM (Manufacturer)] = '" + tb_OEM.Text + "', "
                If (IsNumeric(tb_MTBF.Text)) Then str_SQL += "[MTBF (Hours)] = " + tb_MTBF.Text + ", " Else str_SQL += "[MTBF (Hours)] = null, "
                If (IsNumeric(tb_Failure_Rate.Text)) Then str_SQL += "[Failure Rate] = " + tb_Failure_Rate.Text + ", " Else str_SQL += "[Failure Rate] = null, "
                If (IsNumeric(tb_Year_Of_Support.Text)) Then str_SQL += "[Repair Turn Around Time] = " + tb_Year_Of_Support.Text + ", " Else str_SQL += "[Repair Turn Around Time] = null, "
                If (IsNumeric(tb_Utilization_Rate.Text)) Then str_SQL += "[Utilization Rate] = " + tb_Utilization_Rate.Text + ", " Else str_SQL += "[Utilization Rate] = null, "
                If (IsNumeric(tb_Population.Text)) Then str_SQL += "[Population] = " + tb_Population.Text + ", " Else str_SQL += "[Population] = null, "
                If (IsNumeric(tb_Spares_Required.Text)) Then str_SQL += "[Spares Required] = " + tb_Spares_Required.Text + ", " Else str_SQL += "[Spares Required] = null, "
                If (IsNumeric(tb_Price_Per_Unit.Text)) Then str_SQL += "[Testing] = " + tb_Price_Per_Unit.Text + ", " Else str_SQL += "[Testing] = null, "
                If (IsNumeric(tb_Total_Cost_Per_Line_Item.Text)) Then str_SQL += "[Price Per Unit] = " + tb_Total_Cost_Per_Line_Item.Text + ", " Else str_SQL += "[Price Per Unit] = null, "
                If (IsNumeric(tb_Total_Uptime.Text)) Then str_SQL += "[Total Cost Per Line Item] = " + tb_Total_Uptime.Text + " " Else str_SQL += "[Total Cost Per Line Item] = null "
                str_SQL += "WHERE VAL([S/N]) = " + tb_SN.Text

                cnn.Open()
                cmd.Connection = cnn
                cmd.CommandType = CommandType.Text
                cmd.CommandText = str_SQL
                cmd.ExecuteNonQuery()
                cnn.Close()

                MessageBox.Show("Record has been updated successfully!!", "", MessageBoxButtons.OK, MessageBoxIcon.Information)
            End If
        Catch ex As Exception
            MessageBox.Show(ex.Message.ToString())
        End Try