[.NET]Error ตรง "Conversion from type 'DBNull' to type 'integer' is not valid." แก้ยังไงดีครับ

    Private Sub cmdSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdSave.Click
        If txtEmployeeID.Text = "" Then
            MessageBox.Show("กรุณาระบุรหัสพนักงาน !!!", "ผลการตรวจสอบ", MessageBoxButtons.OK, MessageBoxIcon.Information)
            txtEmployeeID.Focus()
            Exit Sub
        End If

        If lsvPrintColorList.Items.Count = 0 Then
            MessageBox.Show("กรุณาป้อนรายการเบิกหมึกพิมพ์ !!!", "ผลการตรวจสอบ", MessageBoxButtons.OK, MessageBoxIcon.Information)
            txtPrintCLID.Focus()
            Exit Sub
        End If

        Dim sqlDisclose As String = ""
        Dim comDisclose As OleDbCommand = New OleDbCommand

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

        Try
            If MessageBox.Show("คุณต้องการบันทึกรายการเบิกหมึกพิมพ์ ใช่หรือไม่?", "คำยืนยัน", MessageBoxButtons.YesNo, MessageBoxIcon.Question) = DialogResult.Yes Then

                AutoGenerateTranID()

                sqlDisclose = "INSERT INTO Disclose (TransID,EmployeeID) "
                sqlDisclose &= " VALUES('" & LastTransID & "',"
                sqlDisclose &= "'" & txtEmployeeID.Text & "')"

                With comDisclose
                    .CommandType = CommandType.Text
                    .CommandText = sqlDisclose
                    .Connection = Conn
                    .ExecuteNonQuery()
                End With

                Dim i As Integer = 0
                Dim tmpPrintCLID As String = ""

                Dim sqlPrintColor As String = ""
                Dim tmpColorInShop As Integer = 0
                Dim tmpColorInDisclose As Integer = 0

                Dim tmpDiscloseNum As Integer = 0
                Dim tmpDate_Disclose As Date


                tmpDate_Disclose = Date.Now

                For i = 0 To lsvPrintColorList.Items.Count - 1
                    sqlDisclose = "INSERT INTO DiscloseDetail(TransID,PrintCLID,Date_Disclose,DiscloseNum)"
                    sqlDisclose &= " VALUES('" & LastTransID & "',"

                    tmpPrintCLID = lsvPrintColorList.Items(i).SubItems(0).Text

                    tmpDiscloseNum = CInt(lsvPrintColorList.Items(i).SubItems(2).Text)

                    sqlDisclose &= "'" & tmpPrintCLID & "',"
                    sqlDisclose &= "'" & tmpDate_Disclose & "',"
                    sqlDisclose &= tmpDiscloseNum & ")"

                    With comDisclose
                        .CommandText = sqlDisclose
                        .ExecuteNonQuery()
                    End With

                    sqlPrintColor = "SELECT PrintCLID,ColorInShop,ColorInDisclose FROM PrintColor"
                    sqlPrintColor &= " WHERE (PrintCLID='" & tmpPrintCLID & "')"

                    da.SelectCommand.CommandText = sqlPrintColor
                    da.Fill(ds, "PrintColor")

                    tmpColorInShop = CInt(ds.Tables("PrintColor").Rows(0).Item("ColorInShop"))
                    tmpColorInDisclose = CInt(ds.Tables("PrintColor").Rows(0).Item("ColorInDisclose"))
                    ds.Tables("PrintColor").Clear()

                    sqlDisclose = "UPDATE PrintColor"
                    sqlDisclose &= " SET ColorInShop=" & tmpColorInShop - tmpDiscloseNum & ","
                    sqlDisclose &= " ColorInDisclose=" & tmpColorInDisclose + tmpDiscloseNum
                    sqlDisclose &= " WHERE (PrintCLID='" & tmpPrintCLID & "')"

                    With comDisclose
                        .CommandText = sqlDisclose
                        .ExecuteNonQuery()
                    End With
                Next


                MessageBox.Show("บันทึกรายการเบิกหมึกพิมพ์เรียบร้อยแล้ว !!!", "ผลการทำงาน", MessageBoxButtons.OK, MessageBoxIcon.Information)


                ClearAllCustomerData()
                ClearAllPrintColorData()
                lsvPrintColorList.Items.Clear()


                cboDepartment.SelectedIndex = 0
                txtEmployeeID.Enabled = True
                txtEmployeeID.Focus()
            End If

        Catch ErrProcess As Exception
            MessageBox.Show("ไม่สามารถบันทึกรายการเบิกหมึกพิมพ์ได้ เนื่องจาก " & ErrProcess.Message, "ข้อผิดพลาด", MessageBoxButtons.OK, MessageBoxIcon.Warning)
            Exit Sub
        End Try
    End Sub