Blog: Posts from September, 2016

Conditional visibility on data fields and categories allows hiding or showing page elements based on field values. View templates give the ability to define custom presentations. When a custom template is defined for the view, the client library is not able to determine which page elements should be displayed or hidden based on the conditional visibility expressions. As such, the creator of view templates must mark up the template in order to bind these expressions with the correct elements.

When the template has been correctly defined, data fields, categories, and even custom page elements will be able to displayed or hidden depending on field values. For example, a large label is displayed in the sample below when the order has been shipped past the required date.

Let’s use the create form for Orders in the Northwind sample database.

Arranging Data Fields into Categories

First, let’s rearrange the data fields into multiple categories, in order to control visibility of each category, instead of each individual data field. The user will only be able to enter shipping information if a shipped date is assigned.

Start the Project Designer. In the Project Explorer, switch to the Controllers tab. Right-click on “Orders / createForm1” view node, and press New Category.

Define the following settings:

$row.ShippedDate != null

Press OK to save the category. Next, drag data fields ShipVia, Freight, ShipName, ShipAddress, ShipCity, ShipRegion, ShipPostalCode, and ShipCountry into the new category.

Adding Data Field Visibility

Users should not be able to set the shipped date until the order date has been set. Let’s add a data field conditional visibility expression to ShippedDate data field.

Double-click on “Orders / Views / createForm1 / c1 – New Orders / ShippedDate” data field node.

Make the following change:

$row.OrderDate != null

Press OK to save the data field.

Adding the View Template

Let’s add a custom view template for editForm1 of Orders controller.

On the toolbar, press Develop to open the project in Visual Studio. In the Solution Explorer, right-click on the “WebSite” node and press “Add / New Folder”.

Give this new folder the name “Views”. Next, right-click on the folder and press “Add / HTML Page”.

Give this page the name “Orders.createForm1.html”. Replace the contents of the file with the following:

<div data-container="collapsible" data-header-text="New Order">
    <div data-container="row">
        <div data-control="description">Enter new order information below.</div>
    </div>
    <div data-container="row">
        <div data-control="label" data-field="CustomerID">CustomerID</div>
        <div data-control="field" data-field="CustomerID">CustomerID</div>
    </div>
    <div data-container="row">
        <div data-control="label" data-field="EmployeeID">EmployeeID</div>
        <div data-control="field" data-field="EmployeeID">EmployeeID</div>
    </div>
    <div data-container="row">
        <div data-control="label" data-field="OrderDate">OrderDate</div>
        <div data-control="field" data-field="OrderDate">OrderDate</div>
    </div>
    <div data-container="row">
        <div data-control="label" data-field="RequiredDate">RequiredDate</div>
        <div data-control="field" data-field="RequiredDate">RequiredDate</div>
    </div>
    <div data-container="row" data-visibility="f:ShippedDate">
        <div data-control="label" data-field="ShippedDate">ShippedDate</div>
        <div data-control="field" data-field="ShippedDate">ShippedDate</div>
    </div>
    <div data-container="row" data-visible-when="$row.RequiredDate < $row.ShippedDate">
        <h3 style="color:red">WARNING: THIS ORDER HAS BEEN SHIPPED LATE</h3>
    </div>
</div>
<div data-container="collapsible" data-header-text="Ship Info" data-visibility="c:c2">
    <div data-container="row">
        <div data-control="description">Enter shipping information below.</div>
    </div>
    <div data-container="row">
        <div data-control="label" data-field="ShipVia">ShipVia</div>
        <div data-control="field" data-field="ShipVia">ShipVia</div>
    </div>
    <div data-container="row">
        <div data-control="label" data-field="Freight">Freight</div>
        <div data-control="field" data-field="Freight">Freight</div>
    </div>
    <div data-container="row">
        <div data-control="label" data-field="ShipName">ShipName</div>
        <div data-control="field" data-field="ShipName">ShipName</div>
    </div>
    <div data-container="row">
        <div data-control="label" data-field="ShipAddress">ShipAddress</div>
        <div data-control="field" data-field="ShipAddress">ShipAddress</div>
    </div>
    <div data-container="row">
        <div data-control="label" data-field="ShipCity">ShipCity</div>
        <div data-control="field" data-field="ShipCity">ShipCity</div>
    </div>
    <div data-container="row">
        <div data-control="label" data-field="ShipRegion">ShipRegion</div>
        <div data-control="field" data-field="ShipRegion">ShipRegion</div>
    </div>
    <div data-container="row">
        <div data-control="label" data-field="ShipPostalCode">ShipPostalCode</div>
        <div data-control="field" data-field="ShipPostalCode">ShipPostalCode</div>
    </div>
    <div data-container="row">
        <div data-control="label" data-field="ShipCountry">ShipCountry</div>
        <div data-control="field" data-field="ShipCountry">ShipCountry</div>
    </div>
</div>

Notice that there are three highlighted pieces in the sample above.

The yellow highlight shows how to apply data field-level visibility to an element by using the attribute “data-visibility”, and setting the value to “f:” followed by the name of the field. This will inherit the visibility from the field “ShippedDate”.

The green highlight shows how to apply category-level visibility to an element. Use the attribute “data-visibility”, and set the value to “c:” followed by the category ID. The example will inherit visibility from the category “c2”.

The orange highlight shows how to use custom JavaScript expressions to set visibility. Use the attribute “data-visible-when”, and set the value to your JavaScript visibility expression.

Switch back to the browser, navigate to the Orders page, and create a new order. Notice that the OrderDate data field, custom header, and shipping category are hidden.

Enter a value for Order Date. Notice that the Shipped Date data field will appear.

Enter a value for Shipped Date. The Ship Info category will appear.

If the Shipped Date is after the Required Date, the warning text will appear.

In businesses that require a lot of driving and tracking packages, it is invaluable to estimate a driving distance between two different addresses or sets of latitude/longitude. Starting in release 8.5.11.0, C# and Visual Basic business rules now have access to the CalculateDistance() method. This method will query the Google Distance Matrix API to estimate driving distance.

It is required to obtain and add a Maps API Identifier to your project in order to use this feature.

Please make sure to follow Google Maps APIs Terms Of Service. Of note is section 10.5.d, which restricts long-term storage of Content.

Let’s add a custom action to the Employees page that, when pressed, will display how far the employee lives from the main office using a code business rule.

First, we need to add an action that will be accessible to the user in order to trigger the code.

Start the Project Designer. In the Project Explorer, switch to the Controllers tab. Right-click on “Employees / Actions / ag1 (Grid)” node, and press New Action.

Enter the following settings:

Press OK to save. Next, let’s create a business rule that will be triggered when the user presses the action. Right-click on “Employees / Business Rules”, and press New Business Rule.

Enter the following properties:

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

When generation is complete, press “Edit Rule” on the action bar to open the file in Visual Studio.

Replace the contents with the following:

C#:

using System.Data;
using MyCompany.Data;
using MyCompany.Models;

namespace MyCompany.Rules
{
    public partial class EmployeesBusinessRules : MyCompany.Data.BusinessRules
    {
        
        /// <summary>
        /// This method will execute in any view for an action
        /// with a command name that matches "Custom" 
        /// and argument that matches "DistanceFromHQ".
        /// </summary>
        [Rule("r100")]
        public void r100Implementation(EmployeesModel instance)
        {
            // combine address pieces with ","
            string sourceAddress = string.Join(",", instance.Address, instance.City,
                instance.Region, instance.PostalCode, instance.Country);
            string destinationAddress = "1 Microsoft Way,Redmond,Washington";

            // get distance and calculate miles
            decimal meters = CalculateDistance(sourceAddress, destinationAddress);
            decimal miles = meters * 0.00062137m;

            // show result
            if (meters == 0)
                Result.ShowAlert("No path found.");
            else
                Result.ShowAlert("Distance from HQ is " + meters 
                    + " meters, or " + miles + " miles");
        }
    }
}

Visual Basic:

Imports MyCompany.Data
Imports MyCompany.Models

Namespace MyCompany.Rules
    
    Partial Public Class EmployeesBusinessRules
        Inherits MyCompany.Data.BusinessRules

        ''' <summary>
        ''' This method will execute in any view for an action
        ''' with a command name that matches "Custom" 
        ''' and argument that matches "DistanceFromHQ".
        ''' </summary>
        <Rule("r100")>
        Public Sub r100Implementation(ByVal instance As EmployeesModel)
            ' combine address pieces with ","
            Dim sourceAddress = String.Join(",", instance.Address, instance.City,
                    instance.Region, instance.PostalCode, instance.Country)
            Dim destinationAddress = "1 Microsoft Way,Redmond,Washington"

            ' get distance and calculate miles
            Dim meters = CalculateDistance(sourceAddress, destinationAddress)
            Dim miles = meters * 0.00062137D

            ' show result
            If (meters = 0) Then
                Result.ShowAlert("No path found.")
            Else
                Result.ShowAlert("Distance from HQ is " & meters &
                                 " meters, or " & miles & " miles")
            End If
        End Sub
    End Class
End Namespace

Switch back to the web browser, and press the three dot menu button next to any row to reveal the grid action menu.

Press “Distance From HQ” action, and a message box will display the distance.

Note that it is also possible to pass a latitude and longitude by separating the values with a comma, such as in the following example:

CalculateDistance(instance.Latitude + "," + instance.Longitude, destinationAddress)