Blog: Posts from January, 2013

The Filter Field property specifies the foreign key field on the child data view that will be filtered in a master-detail relationship.

Drag & drop techniques can be used in order to automatically configure the relationship. For example, the picture below shows how to configure CustomerID as the filter field between Customers and Orders data views.

However, when the master data view has a compound primary key, the relationship must be configured manually.

Let’s add a Notes table to the database that will have a compound primary key that refers to OrderID and ProductID.

The table will then be added to the project. A Notes data view will be added to the default Orders page in order to compose a three-level master-detail relationship.

Creating the Notes Table

Start SQL Server Management Studio and connect to your database. In the Object Explorer, right-click on Databases / Northwind node, and press New Query.

Paste in the following script:

create table dbo.Notes(
    IDofOrder int not null,
    IDofProduct int not null,
    Notes ntext not null,
    Created datetime not null,
     constraint PK_Notes primary key clustered
    (
        IDofOrder asc,
        IDofProduct asc
    )
)

alter table dbo.Notes add constraint FK_Notes_OrderDetails_OrderID foreign key (IDofOrder)
references dbo.Orders (OrderID)

alter table dbo.Notes add constraint FK_Notes_OrderDetails_ProductID foreign key (IDofProduct)
references dbo.Products (ProductID)

Click on Execute on the toolbar to run the query.

Adding the Table to the Project

Start the web application generator. Click on the project name, and press Refresh. Check the box next to dbo.Notes table to add it to the project, and press Refresh.

Adding Notes Data View

Right-click on Notes controller node, and press Copy.

Switch back to the Pages tab. Right-click on Customers / Orders page node, and press Paste. The data controller will be instantiated as a data view in a new container.

Configuring Master-Detail Relationship

Double-click on Customers /Orders / c101/ view4(Notes) node.

Make the following changes:

Press OK to save.

Viewing the Results

On the Project Designer toolbar, press Browse. Navigate to the Orders page. Select an order from the list, and then select an order detail. The Notes data view will appear underneath, filtered by OrderID and ProductID.

The When Client Script property allows controlling the display of an action based on a JavaScript expression. When the expression evaluates to true, the action is displayed. When it evaluates to false, the action is hidden. This property can be used to prevent users from editing a record based on certain conditions.

The property may be manually set in the Project Designer for every action that needs to be hidden. However, this may result in a large number of changes to be made. If the requirements of the web application were to change, all actions would need to be modified.

A simpler method would be to use virtualization node set plugins. The data controllers will be virtualized to conditionally add a When Client Script parameter for a subset of actions. When project requirements change, the virtualization code can be modified once.

For example, suppose that the web application described in the When Client Script tutorial has been created. The three Edit actions in the Orders controller are not displayed when the Status field of the order is set to “Committed”.

However, orders may still be deleted and order details can be modified. Let’s implement virtualization node set plugins to ensure that the user cannot make any changes to committed orders.

First, make sure to clear any When Client Script values that have been set previously.

Including Status Field in Order Details Controller

In order to prevent order details from being edited, the Status field must be included in the Order Details controller using denormalization.

Start the web application generator. Click on the project name, select Settings, and activate Business Logic Layer. Select Denormalization Map from the list, and make the highlighted addition:

Press Finish to navigate to the Summary page. Click on Refresh, and check the box next to OrderDetails controller. Press Refresh and confirm.

On the Summary page, press Design to activate the Project Designer. In the Project Explorer, switch to the Controllers tab. Double-click on OrderDetails / Fields node.

Mark the field as hidden.

Press OK to save. Drop OrderStatus (String(50), read-only) field node onto OrderDetails / Views / grid1 node.

Adding Business Rule

Right-click on Orders controller node and press Edit Handler in Visual Studio.

The handler file will open in Visual Studio. Append the SharedBusinessRules class with the two highlighted methods:

C#:

using System;
using System.Data;
using System.Collections.Generic;
using System.Linq;
using MyCompany.Data;

namespace MyCompany.Rules
{
    public partial class SharedBusinessRules : MyCompany.Data.BusinessRules
    {

        public SharedBusinessRules()
        {
        }

        protected override void EnumerateDynamicAccessControlRules(string controllerName)
        {
            if (Context.Request.UrlReferrer != null)
            {
                if (Context.Request.UrlReferrer.ToString().ToLower().Contains("orderform.aspx"))
                    RegisterAccessControlRule("OrderID",
                        "select OrderID from Orders where Status = 'Draft'",
                        AccessPermission.Allow);
                else
                    RegisterAccessControlRule("OrderID",
                        "select OrderID from Orders where Status = 'Committed'",
                        AccessPermission.Allow);
            }
        }

        public override bool SupportsVirtualization(string controllerName)
        {
            if (controllerName == "Orders" || controllerName == "OrderDetails")
                return true;
            else
                return false;
        }
        protected override void VirtualizeController(string controllerName)
        {
            if (controllerName == "Orders")
                NodeSet().SelectActions("Edit", "Delete")
                    .WhenClientScript("[Status] != 'Committed'");
            else if (controllerName == "OrderDetails")
                NodeSet().SelectActions("Edit", "Delete", "New", "Duplicate")
                    .WhenClientScript("[OrderStatus] != 'Committed'");
        }
    }
}

Visual Basic:

Imports MyCompany.Data
Imports System
Imports System.Collections.Generic
Imports System.Data
Imports System.Linq

Namespace MyCompany.Rules

    Partial Public Class SharedBusinessRules
        Inherits MyCompany.Data.BusinessRules

        Public Sub New()
            MyBase.New()
        End Sub

        Protected Overrides Sub EnumerateDynamicAccessControlRules(controllerName As String)
            If Context.Request.UrlReferrer <> Nothing Then
                If Context.Request.UrlReferrer.ToString().ToLower().Contains("orderform.aspx") Then
                    RegisterAccessControlRule("OrderID",
                                            "select OrderID from Orders where Status = 'Draft'",
                                            AccessPermission.Allow)
                Else
                    RegisterAccessControlRule("OrderID",
                                            "select OrderID from Orders where Status = 'Committed'",
                                            AccessPermission.Allow)
                End If
            End If
        End Sub

        Public Overrides Function SupportsVirtualization(controllerName As String) As Boolean
            If controllerName = "Orders" Or controllerName = "OrderDetails" Then
                Return True
            Else
                Return False
            End If
        End Function
        Protected Overrides Sub VirtualizeController(controllerName As String)
            If controllerName = "Orders" Then
                NodeSet().SelectActions("Edit", "Delete").WhenClientScript(
                    "[Status] != 'Committed'")
            ElseIf controllerName = "OrderDetails" Then
                NodeSet().SelectActions("Edit", "Delete", "New", "Duplicate").WhenClientScript(
                    "[OrderStatus] != 'Committed'")

            End If
        End Sub
    End Class
End Namespace

The business rule will virtualize the Orders and OrderDetails controllers. For Orders, all Edit and Delete actions will be selected. For OrderDetails, all Edit, Delete, New, and Duplicate actions will be selected. Then, a When Client Script parameter will be assigned to hide the actions when the Status field is equal to “Committed”.

Viewing the Results

Save the file, and run the web application in your browser. Navigate to the Orders page. The Edit and Delete actions are no longer available in the user interface.

Select an order to view the order details. All Edit, Delete, New, and Duplicate actions will not be available.