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An End-To-End LightSwitch HTML Example

, 15 Jun 2013 CPOL
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Step-by-step tutorial to create a HTML5 LightSwitch application

Download the 63Mb project from here: http://code.msdn.microsoft.com/vstudio/Online-Ordering-System-An-5a6d9134

An End-To-End LightSwitch HTML Example

Note: See the updated Visual Studio 2013 version here: An End-To-End Visual Studio LightSwitch 2013 HTML5 Application

Live Demo: https://endtoendexample.lightswitchhelpwebsite.com/Client/default.htm (use your username and password from http://LightSwitchHelpWebsite.com)

In this article we will create an end-to-end HTML application in Visual Studio LightSwitch. The purpose is to demonstrate how LightSwitch allows you to create professional business applications that would take a developer days to create. With LightSwitch you can create such applications in under an hour.

You can download LightSwitch at: http://www.microsoft.com/visualstudio/en-us/lightswitch.

The Scenario

In this example, we will be tasked with producing an application that meets the following requirements for a order tracking system:

  • Products
    • Add Products
    • Edit Products
    • Delete Products
  • Orders
    • Add Orders
    • Edit Orders
      • Add Order Details
      • Edit Order Details
      • Delete Order Details
    • Delete Orders
  • Business Rules
    • Allow the current user to only see their orders
    • Show the number of orders for the current user
    • Allow an Administrator to see all orders
  • Features
    • Display the number of orders for a User

Creating The Application

image

Open Visual Studio and select File, then New Project.


image

Create a new LightSwitch HTML Application (note you must have the LightSwitch HTML Client installed).

image

The application will be created.

image

Right-Click on the Server node in the Solution Explorer and select Add Table.

image

Click on the table name to edit it.

Change the table name to Product.

image

Also, add ProductName and ProductPrice fields to the table.

image

Click the Save button to save the table.

image

Create an Order table (with the fields in the image above).

image

Create an OrderDetail table (with the fields in the image above).

Create Relationships

You will always want to make relationships when tables are related. This allows for optimal LightSwitch application construction. When creating queries, having relationships defined allows you to simply type a period (“.”) and traverse from one entity to another. This saves a lot of coding work and reduces coding errors.

When creating user interfaces, defining relationships allows you to save a lot of coding work because LightSwitch will be able to automatically associate, for example, Order Details with their associated Order.

image

Click on the Relationship button to create a relationship between the Order Detail and the Product table.

image

A box will appear. Select Product for the To table and click OK (ensure the other fields match the image above).

image

You will see that a relationship has been created. you can double-click on the line to edit the relationship.

image

Click on the Relationship button again and make a new relationship to the Order table.

Create a Filter

One feature we are required to implement is to only show a user their own orders (and allow an administrator to see all orders). We must keep in mind that all LightSwitch applications expose all data via OData so we must always set security in the server-side code not only in the client-side code (such as the HTML or Silverlight LightSwitch clients).

image

The first thing we need to do is turn on security.

image

Next, we open the Orders table and select Write Code, then Orders_Filter.

Use the following code for the method:

        partial void Orders_Filter(ref Expression<Func<Order, bool>> filter)
        {
            // Only show the Orders for the current user
            filter = (x => x.UserName == this.Application.User.Identity.Name);
        }

All data that access this table will pass through this filter.

Set Defaults

Keeping in mind that we must set everything that relates to security in server-side code, we realize that marking orders with the UserName of the current user must be set using server-side code.

image

Open the Orders table and select Write Code, then Orders_Inserting. Use the following code for the method:

        partial void Orders_Inserting(Order entity)
        {
            // Set the Username 
            entity.UserName = this.Application.User.Name;
        }

Do the same for the Orders_Updating event.

Later, we will also set the UserName using client-side code, however, the server side code will always run and overwrite any value set client-side.

Create a Query

Another feature we are required to implement is to show the number of orders for the current user. We will make a query that we can later consume from the client-side.

image

Right-click on the Orders table and select Add Query.

image

Name the query OrdersForUser by clicking on the title and editing it. Save it first, then select the OrdersForUser PreprocessQuery.

use the following code for the method:

        partial void OrdersForUser_PreprocessQuery(ref IQueryable<Order> query)
        {
            // Only show the Orders for the current user
            query = query.Where(x => x.UserName == this.Application.User.Identity.Name);
        }

Create The User Interface For Products

image

We will first create a screen that will allow us to see Products.

Right-click on the Client node in the Solution Explorer and select Add Screen.

image

Create a Browse Data Screen using the Products table.

image

The screen will be created.

image

We will now create a screen that will allow us to edit a Product that is selected.

Click on the Products List and in its Properties select the Item Tap action.

image

Select Choose an existing method, choose editSelected.

image

We will now connect the Browse Data Screen to a new Edit Screen.

For Navigate To, select (New Screen…) and click OK.

image

The Add New Screen box will show. Select only the Product Details and click OK.

image

The screen will be created.

image

Now we will add a button that will create a new Product.

Return to the Browse Products screen.

image

Select the Command Bar, then Add then Choose an existing method, then AddAndEditNew.

image

For Navigate To, select Add Edit Product (the screen created in the earlier step) and click OK.

image

Hit F5 to run the application.

Click the ADD PRODUCT button to add a Product.

image

Add a product and click the Save button to save it.

image

The products will show in a list.

Create The Main Page

image

We will now create the Main screen

Create a new screen called Main using the Orders table for Screen Data.

image

Select the Item Tap action for the List control.

image

We will now connect the screen to a new Edit screen.

For Navigate To, select (New Screen…) and click OK.

image

The Add New Screen box will show. Select the Order Details and Order OrderDetails and click OK.

image

The screen will be created.

Format The Add Edit Order Screen

image

Change the User Name Text Box to a Text label.

image

We will now allow the user to select an Order Detail and edit it in a new screen.

Click on the Order Details List control and then click on the Tap action in its Properties.

Select OrderDetails.editSelected and then Navigate To: (New Screen…).

image

The Add New Screen box will show.

Select the OrderDetail Details and click OK.

image

The screen will be created.

Format The Add Order Detail Edit Screen

image

Right-click on the Rows Layout for the Order dropdown and Delete it.

We don’t need to show the Order (and allow it to be changed) because it will be set by the time the user gets to this screen.

We will return to this screen later to add a delete button. That delete button will require custom JavaScript and we will show how to do that later.

Therefore, we are done with this screen for now.

Create an Add Order Detail Button

image

We will create a button to allow the user to add a new Order Detail.

Return to the AddEditOrder screen.

Open the Command Bar for the Order Details Tab.

Select Add to add a new button.

In the Add Button popup, select OrderDetails.addAndEditNew and Navigate To: Add Edit Order Detail (the screen you created in the earlier step).

Create an Add Order Button

image

We will create a button to allow the user to add a new Order.

Return to the Main screen.

Open the Command Bar.

Select Add to add a new button.

In the Add Button popup, select Orders.addAndEditNew and Navigate To: Add Edit Order (the screen you created in the earlier step).

image

In the Solution Explorer, right-click on the Main page and select Set as Home Screen.

Setting Default Values

image

If we run the application, and click the Add Order button…

image

… and try to create an Order it wont save.

We are missing the User Name. We have already added code to overwrite the User Name with the current user, but since we made it a required field, it must still be supplied. We could just make the User Name field a text box and allow the user to type it in, but we can use ServerApplicationContext to insert it client side automatically.

See the following article for a step by step tutorial: Retrieving The Current User In The LightSwitch HTML Client.

Using Server Application Context

We will now create a file handler that will use the Server Application Context API to retrieve the currently logged in user’s User Name. We will then call that handler from JavaScript code on the client-side, to fill in the value on the screen.

image

In the Solution Explorer, click on the project and switch to File View.

image

Right-click on the Server/Web folder and select Add then New Item.

image

Create a new Generic Handler.

(note: you must create the file from scratch so that the proper references are added to the project. If you simply copy and paste, or drag and drop the file into the project, it will not work.)

Use the following code for the file:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
namespace LightSwitchApplication.Web
{
    public class GetUserName : IHttpHandler
    {
        public void ProcessRequest(HttpContext context)
        {
            using (var serverContext = ServerApplicationContext.CreateContext())
            {
                context.Response.ContentType = "text/plain";
                context.Response.Write(serverContext.Application.User.Name);
            }
        }
        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}

image

Switch back to Logical View, open the Order table, select the Client (tab), Write Code, and then the created method.

Use the following code for the method:

myapp.Order.created = function (entity) {
    // Set the default date for the Order
    entity.OrderDate = new Date();
    // Using a Promise object we can call the CallGetUserName function
    msls.promiseOperation(CallGetUserName).then(function PromiseSuccess(PromiseResult) {
        // Set the result of the CallGetUserName function to the 
        // UserName of the entity
        entity.UserName = PromiseResult;
    });
};

// This function will be wrapped in a Promise object
function CallGetUserName(operation) {
    $.ajax({
        type: 'post',
        data: {},
        url: '../web/GetUserName.ashx',
        success: operation.code(function AjaxSuccess(AjaxResult) {
            operation.complete(AjaxResult);
        })
    });
}

(note: see Using Promises In Visual Studio LightSwitch for more information on using the msls.promiseOperation)

image

When we run the application, the User Name and Date are now set to their default values when a new record is created.

You will now be able to create and save records.

Formatting Output

image

When we look at the Order Details, we see that it is not formatted the way we want.

image

We return to the Add Edit Order screen and change the Order Detail Summary control to a Custom Control.

image

In the Properties for the control we select Edit Render Code.

We use the following code:

myapp.AddEditOrder.RowTemplate_render = function (element, contentItem) {
    // We need to wait until the Products for the Order Detail are loaded
    // so we create a binding to "value.Product.ProductName"
    // When the data is loaded the binding will be raised
    // We will then have all the data required for our display
    contentItem.dataBind("value.Product.ProductName", function (newValue) {
        // clear the element
        element.innerHTML = "";
        // Create a template
        var itemTemplate = $("<div></div>");
        // Get the Product name and quantity
        var ProductName = contentItem.value.Product.ProductName;
        var ProductQuantity = "";
        if (contentItem.value.Quantity !== undefined) {
            ProductQuantity = ' [' + contentItem.value.Quantity + ']';
        }
        // Create the final display
        var FinalName = $("<h2>").text(ProductName + ProductQuantity);
        // Complete the template
        FinalName.appendTo($(itemTemplate));
        itemTemplate.appendTo($(element));
    });
};
 

(note: for more information about Promises see: Using Promises In Visual Studio LightSwitch.
Also see: Writing JavaScript That Implements The Binding Pattern In Visual Studio LightSwitch)

image

When we run the application, the output is formatted as we desire.

Calling A Custom Query

Next, we will call the query we created earlier.

image

Open the Main screen, select Add Data Item, and create a Integer property.

image

Drag and drop the property from the View Model to the screen layout.

image

In the Properties, make the label Left-aligned.

image

To set the value for the property, select Write Code, then the created method.

Use the following code:

myapp.Main.created = function (screen) {
    myapp.activeDataWorkspace.ApplicationData.OrdersForUser().execute().then(function (results) {
        var TotalCountOfOrders = CountOrders(results);
        screen.TotalOrdersForCurrentUser = TotalCountOfOrders.toString();
    });
};
function CountOrders(Orders) {
    var TotalOrders = 0;
    var orders = Orders.results;
    orders.forEach(function (order) {
        TotalOrders = TotalOrders + 1;
    });
    return TotalOrders;
}

image

When we run the application we see a count of the Orders.

Easy Formatting

image

When we look at the Main screen, we see that it shows the User Name and we would like to show the Order Date.

image

In Visual Studio, open the Main screen.

Change the Order Summary control to a Rows Layout.

image

Right-click on the User Name label and delete it.

image

When we run the application, we will see the Order Date.

Deleting A Record

image

Open the Add Edit Order Detail screen and add a button to the Command Bar.

Make a Delete method for the button.

image

Right-click on the Delete method in the View Model and select Edit Execute Code.

use the following code for the method:

myapp.AddEditOrderDetail.Delete_execute = function (screen) {
    screen.OrderDetail.deleteEntity();
    return myapp.commitChanges().then(null, function fail(e) {
        myapp.cancelChanges();
        throw e;
    });
};

image

When you run the application, you will be able to delete the selected Order Detail.

image

You will need to Save the changes to actually delete the record.

We can also add a Delete button to the Add Edit Order screen using the following code:

myapp.AddEditOrder.Delete_execute = function (screen) {
    screen.Order.deleteEntity();
    myapp.commitChanges().then(null, function fail(e) {
        alert(e.message);
        myapp.cancelChanges();
        throw e;
    });
};

image

You will notice that if we try to delete an Order that still has Order Detail records…

image

…it will throw an error because the relationship that we created between the tables earlier was set to not allow an Order to be deleted if there were associated records.

Delete all the Order Details first and then you can delete the Order.

Navigate To A Screen

image

Open the Main screen and create a button that will navigate to the Browse Products screen.

image

The Show Browse Products button will show.

LightSwitch Help Website Articles

Full Control LightSwitch (ServerApplicationContext And Generic File Handlers And Ajax Calls)

Saving Data In The Visual Studio LightSwitch HTML Client (Including Automatic Saves)

Creating A Desktop Experience Using Wijmo Grid In LightSwitch HTML Client

Creating ASP.NET Web Forms CRUD Pages Using ServerApplicationContext

Using Promises In Visual Studio LightSwitch

Retrieving The Current User In The LightSwitch HTML Client

Writing JavaScript That Implements The Binding Pattern In Visual Studio LightSwitch

Implementing The Wijmo Radial Gauge In The LightSwitch HTML Client

Writing JavaScript In LightSwitch HTML Client Preview

Creating JavaScript Using TypeScript in Visual Studio LightSwitch

Theming Your LightSwitch Website Using JQuery ThemeRoller

Using Toastr with Visual Studio LightSwitch HTML Client (Preview)

LightSwitch Team HTML and JavaScript Articles

Visualizing List Data using a Map Control

Enhancing LightSwitch Controls with jQuery Mobile

Custom Controls and Data Binding in the LightSwitch HTML Client (Joe Binder)

Creating Screens with the LightSwitch HTML Client (Joe Binder)

The LightSwitch HTML Client: An Architectural Overview (Stephen Provine)

Writing JavaScript Code in LightSwitch (Joe Binder)

New LightSwitch HTML Client APIs (Stephen Provine)

A New API for LightSwitch Server Interaction: The ServerApplicationContext

Building a LightSwitch HTML Client: eBay Daily Deals (Andy Kung)

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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About the Author

defwebserver
Software Developer (Senior) http://ADefWebserver.com
United States United States
Michael Washington is a Microsoft MVP. He is a ASP.NET and
C# programmer.
He is the founder of
LightSwitchHelpWebsite.com

He has a son, Zachary and resides in Los Angeles with his wife Valerie.

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Comments and Discussions

 
GeneralMy vote of 5 PinprofessionalDVL Patel23-May-14 21:39 
GeneralRe: My vote of 5 Pinmemberdefwebserver24-May-14 3:44 
QuestionHave a 5 PinmemberDuke Carey12-Mar-14 2:26 
AnswerRe: Have a 5 Pinmemberdefwebserver12-Mar-14 2:51 
GeneralRe: Have a 5 PinmemberDuke Carey12-Mar-14 3:01 
GeneralRe: Have a 5 Pinmemberdefwebserver12-Mar-14 3:18 
GeneralRe: Have a 5 Pinmemberdefwebserver18-Mar-14 19:29 
GeneralMy vote of 5 Pinmembercsharpbd23-Feb-14 9:35 
GeneralRe: My vote of 5 Pinmemberdefwebserver23-Feb-14 10:01 
QuestionCan you have mutiple items returned in using promises and web based .ashx files? PinmemberLyndon Sundmark24-Aug-13 11:06 
AnswerRe: Can you have mutiple items returned in using promises and web based .ashx files? Pinmemberdefwebserver24-Aug-13 12:17 
QuestionHow does authentication of users work in this project? PinprofessionalNadine Whitfield21-Jul-13 15:43 
AnswerRe: How does authentication of users work in this project? Pinmemberdefwebserver21-Jul-13 16:03 
QuestionRe: How does authentication of users work in this project? Pinprofessionalnwhitfield22-Jul-13 20:04 
AnswerRe: How does authentication of users work in this project? Pinmemberdefwebserver23-Jul-13 3:28 
Generalthnaks alot Pinmembershbnq422vb12-Jul-13 21:24 
Generalproblem with username Pinmembershbnq422vb12-Jul-13 21:41 
GeneralRe: problem with username Pinmemberdefwebserver13-Jul-13 3:30 
QuestionHow to add a Search bar in Browse View? Pinmemberhyblusea9-Apr-13 6:22 
AnswerRe: How to add a Search bar in Browse View? Pinmemberdefwebserver9-Apr-13 11:16 
GeneralRe: How to add a Search bar in Browse View? Pinmemberhyblusea9-Apr-13 16:27 
GeneralMy vote of 5 PinmemberSRSHINDE8-Apr-13 21:55 
GeneralRe: My vote of 5 Pinmemberdefwebserver9-Apr-13 3:13 
QuestionBest example Pinmembermruvinskiy8-Apr-13 10:55 
AnswerRe: Best example Pinmemberdefwebserver8-Apr-13 11:08 
GeneralRe: Best example Pinmembermruvinskiy8-Apr-13 11:20 
GeneralRe: Best example Pinmemberdefwebserver8-Apr-13 12:47 
GeneralRe: Best example Pinmembermruvinskiy8-Apr-13 13:04 
GeneralMy vote of 5 PinmemberPrasad Khandekar6-Apr-13 11:57 
GeneralRe: My vote of 5 Pinmemberdefwebserver6-Apr-13 12:48 
GeneralMy vote of 5 PinmemberPaga Cession26-Mar-13 7:29 
GeneralRe: My vote of 5 Pinmemberdefwebserver26-Mar-13 8:42 
GeneralWell done! PinmvpEspen Harlinn7-Mar-13 13:25 
GeneralRe: Well done! Pinmemberdefwebserver7-Mar-13 14:07 
QuestionAccess Control through the HTML Client Pinmemberlouis-eyond18-Feb-13 10:26 
AnswerRe: Access Control through the HTML Client Pinmemberdefwebserver18-Feb-13 11:13 
GeneralGreat Example Pinmemberbandi.ramesh15-Feb-13 1:44 
GeneralRe: Great Example Pinmemberdefwebserver15-Feb-13 3:14 
GeneralMy vote of 5 PinmemberMonte Christo12-Feb-13 1:13 
GeneralRe: My vote of 5 Pinmemberdefwebserver12-Feb-13 3:25 
GeneralMy vote of 5 PinmemberEdo Tzumer10-Feb-13 19:57 
GeneralRe: My vote of 5 Pinmemberdefwebserver10-Feb-13 20:12 
QuestionAny stored proc examples? Pinmemberclbyrne10-Feb-13 3:49 
AnswerRe: Any stored proc examples? Pinmemberdefwebserver10-Feb-13 4:04 
See this article:
http://blogs.msdn.com/b/eric_erhardt/archive/2012/04/17/executing-a-simple-stored-procedure-in-lightswitch.aspx[^]. There are many more: http://lmgtfy.com/?q=Visual+Studio+LightSwitch+and+stored+procedures[^].
QuestionEnd-To-End Five Stars PinmemberMember 11026249-Feb-13 15:54 
AnswerRe: End-To-End Five Stars Pinmemberdefwebserver9-Feb-13 15:57 
QuestionExcellent. PinmemberManuelM309-Feb-13 9:25 
AnswerRe: Excellent. Pinmemberdefwebserver9-Feb-13 9:47 
GeneralMy vote of 5 PinmemberRichard Waddell9-Feb-13 8:07 
GeneralRe: My vote of 5 Pinmemberdefwebserver9-Feb-13 8:10 

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