must declare the scalar variable @CustomerID ช่วยทีครับ

 sqltr = Conn.BeginTransaction()
            Try
                sb.Remove(0, sb.Length)
                sb.AppendLine("INSERT INTO Customer ( CustomerID,CustomerName,CustomerType,Telephone,Address1)")
                sb.AppendLine(" VALUES (@CustomerID, @CustomerName, @CustomerType, @Telephone, @Address1)")
                Dim sqlAdd As String
                sqlAdd = sb.ToString()

                With Com
                    .CommandType = CommandType.Text
                    .CommandText = sqlAdd
                    .Connection = Conn
                    .Transaction = sqltr
                    .Parameters.Clear()
                    .Parameters.Add("@CustomerID", SqlDbType.VarChar).Value = txtCustomerNo.Text.Trim()
                    .Parameters.Add("@CustomerName", SqlDbType.NVarChar).Value = txtCusName.Text.Trim()
                    .Parameters.Add("@CustomerType", SqlDbType.NVarChar).Value = txtCustype.Text.Trim()
                    .Parameters.Add("@Telephone", SqlDbType.NVarChar).Value = txtCusTelephone.Text.Trim()
                    .Parameters.Add("@Address1", SqlDbType.NVarChar).Value = txtCusAddress.Text.Trim()


                    .ExecuteNonQuery()
                End With
                sqltr.Commit()
                MessageBox.Show("เพิ่มข้อมูลลูกค้าผู้เช่าใหม่ เรียบร้อยแล้ว !!!", "ผลการทำงาน", MessageBoxButtons.OK, MessageBoxIcon.Information)

                ClearAllData()
                ShowData()
                FormatdgvCustomer()
                txtCustomerNo.Focus()

            Catch ex As Exception
                MessageBox.Show(ex.ToString(), "ผลการทำงาน", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
                sqltr.Rollback()
            End Try