Thursday, October 25, 2012

Order Form Sample–Part 19

When you create a new order detail, the Extended Price field will not be calculated and will only display N/A until you save the record.

The Extended Price field is not being updated when field values are changed.

Let’s make the field automatically update and provide instantaneous feedback to the user.

Switch back to the Project Designer, and double-click on OrderDetails / Fields / ExtendedPrice node.

Change the following settings:

Property Value
The value of this field is calculated by a business rule expression True
Context Fields ProductID, UnitPrice, Quantity, Discount

Press OK to save the field.

Right-click on OrderDetails / Business Rules node, and press New Business Rule.

New Business Rule context menu option for OrderDetails controller.

The field can be updated using an SQL, Code or JavaScript business rule. Pick one of the following three implementations.

SQL Business Rule

Assign the following values:

Property Value
Type SQL
Command Name Calculate
Phase Execute
set @ExtendedPrice = @UnitPrice * @Quantity * (1 - @Discount)

Press OK to save.

Code Business Rule

Assign the following values:

Property Value
Type C# / Visual Basic
Command Name Calculate
Phase Execute

Press OK to save. On the toolbar, press Browse to generate the web app and create the business rule file.

When complete, right-click on OrderDetails / Business Rules / Calculate (Code / Execute) – r101 business rule node, and press Edit Rule in Visual Studio.

Edit Rule in Visual Studio context menu option for a code business rule.

The file will be opened in Visual Studio. Replace the body of the rule with the following implementation:


using System;
using MyCompany.Data;

namespace MyCompany.Rules
    public partial class OrderDetailsBusinessRules : MyCompany.Data.BusinessRules
        public void r101Implementation(int? orderID, 
            string orderCustomerID, 
            string orderCustomerCompanyName, 
            string orderEmployeeLastName, 
            string orderShipViaCompanyName, 
            int? productID, 
            string productProductName, 
            string productCategoryCategoryName, 
            string productSupplierCompanyName, 
            decimal? unitPrice, 
            short? quantity, 
            float? discount, 
            decimal? extendedPrice)
                Convert.ToDecimal(unitPrice) * Convert.ToDecimal(quantity) * 
                (1 - Convert.ToDecimal(discount)));

Visual Basic:

Imports MyCompany.Data
Imports System

Namespace MyCompany.Rules

    Partial Public Class OrderDetailsBusinessRules
        Inherits MyCompany.Data.BusinessRules

        <Rule("r101")> _
        Public Sub r101Implementation(ByVal orderID As Nullable(Of Integer),
                                      ByVal orderCustomerID As String,
                                      ByVal orderCustomerCompanyName As String,
                                      ByVal orderEmployeeLastName As String,
                                      ByVal orderShipViaCompanyName As String,
                                      ByVal productID As Nullable(Of Integer),
                                      ByVal productProductName As String,
                                      ByVal productCategoryCategoryName As String,
                                      ByVal productSupplierCompanyName As String,
                                      ByVal unitPrice As Nullable(Of Decimal),
                                      ByVal quantity As Nullable(Of Short),
                                      ByVal discount As Nullable(Of Single),
                                      ByVal extendedPrice As Nullable(Of Decimal))
                Convert.ToDecimal(unitPrice) * Convert.ToDecimal(quantity) *
                (1 - Convert.ToDecimal(discount)))
        End Sub
    End Class
End Namespace

Save the file.

JavaScript Business Rule

Assign the following values:

Property Value
Type JavaScript
Command Name Calculate
Phase Execute
[ExtendedPrice] = [UnitPrice] * [Quantity] * (1 - [Discount]);

Press OK to save the business rule.

Viewing the Results

On the toolbar, press Browse.

Navigate to the Order Form page, and select an order. Create a new order detail, and select a product. The Extended Price will be calculated using the default values.

New Order Details screen with a selected product and default values. The Extended Price has been calculated.

If you change any of the fields, the Extended Price will be recalculated when the user changes focus from the changed field.

Quantity has been changed and focus was shifted to the Discount field. Extended Price has been recalculated.

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