Inheritance in Visual Studio LightSwitch 2011

Vineet Kumar Saini
12y
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Article

Introduction

Inheritance is a concept of Object Oriented Programming. Inheritance is a mechanism of deriving a new class from a base class. A derived class can inherit the properties of a base class.

In this article you will see inheritance among a tables. In this article I make a parent table (Vehicles) and their child tables Car, Bus, Bike. The child table inherits the properties of the parent table.

Step 1 : First of all open Visual Studio LightSwitch->New project->Select LightSwitch application->Write name of project->Ok.

Step 2 : Click on create new table.

Step 3 : Create a parent table with the name Vehicles. Go to properties of type->Click on choice list->Add value->ok.

Step 4 : Now we will create child tables like Bike, Car, Bus.

Step 5 : Now we will make a relationship among these tables. Like as in the following images.

Step 6 : When we establish relationships among these tables then the vehicles tables will look like as in the following image.

Step 7 : Now we will add a screen. Right-click on screens-Add screen.

Step 8 : Select New Data Screen->Select screen data (Vehicles)->Ok.

Step 9 : Now we will a add details screen for Car, Bike, Bus.

Go to Solution Explorer->Right-click on screen->Add screen->Select Details screen->Change screen name->Unmark checkbox for default details screen->Ok.

In the same manner we will create a Bus details screen and a Bike details screen.

Step 10 : Now we will add a search screen. Go to Solution Explorer->Right click on screen->Add screen->Select search data screen->Select screen data (Vehicles)->Ok.

Step 11 : Now we will add a button. Right-click on Command bar->Add button.

Step 12 : Click on new method->Write name (edit)->Ok.

Step 13 : Expand edit->Select link.

Step 14 : Right click on edit button->Select edit execute code->Write code.

Code

using System;
using System.Linq;
using System.IO;
using System.IO.IsolatedStorage;
using System.Collections.Generic;
using Microsoft.LightSwitch;
using Microsoft.LightSwitch.Framework.Client;
using Microsoft.LightSwitch.Presentation;
using Microsoft.LightSwitch.Presentation.Extensions;
namespace LightSwitchApplication
{
    public partial class SearchVehiclesSet
    {
        partial void Edit_Execute()
        {
            // Write your code here.\
            if (this.VehiclesSet.SelectedItem != null)
            {
                switch (this.VehiclesSet.SelectedItem.Type)
                {
                    case "Car":
                        this.Application.ShowCarDetail(this.VehiclesSet.SelectedItem.Id);
                        break;
                    case "Bus":
                        this.Application.ShowBusDetail(this.VehiclesSet.SelectedItem.Id);
                        break;
                    case "Bike":
                        this.Application.ShowBikeDetail(this.VehiclesSet.SelectedItem.Id);
                        break;
                }
             }
       }
    }
}

Step 15 : Go to CreateNewVehicles Screen->Click on write code->Select CreateNewVehicles_Saved->Write code.

Code

using System;
using System.Linq;
using System.IO;
using System.IO.IsolatedStorage;
using System.Collections.Generic;
using Microsoft.LightSwitch;
using Microsoft.LightSwitch.Framework.Client;
using Microsoft.LightSwitch.Presentation;
using Microsoft.LightSwitch.Presentation.Extensions;
namespace LightSwitchApplication
{
    public partial class CreateNewVehicles
    {
        partial void CreateNewVehicles_InitializeDataWorkspace(global::System.Collections.Generic.List<global::Microsoft.LightSwitch.IDataService>
saveChangesTo)
        {
            // Write your code here.
            this.VehiclesProperty = new Vehicles();
        }
        partial void CreateNewVehicles_Saved()
        {
            // Write your code here.
            this.Close(false);
            Application.Current.ShowDefaultScreen(this.VehiclesProperty);
            switch (this.VehiclesProperty.Type) {
                   case "Car":
                             this.Application.ShowCarDetail(this.VehiclesProperty.Id);
                             break;
                   case "Bus":
                             this.Application.ShowBusDetail(this.VehiclesProperty.Id);
                             break;
                   case "Bike":
                             this.Application.ShowBikeDetail(this.VehiclesProperty.Id);
                             break;
        }
    }
}

Step 16 : Go to vehicles tables->Click on write code->Select VehiclesSet_Inserting->Write code.

Code

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.LightSwitch;
using Microsoft.LightSwitch.Security.Server;
namespace LightSwitchApplication
{
    public partial class ApplicationDataService
    {
        partial void VehiclesSet_Inserting(Vehicles entity)
        {
            switch (entity.Type)
            {
                case "Car":
                    if (entity.Car == null)
                    {
                        entity.Car = new Car();
                    }
                    break;
                case "Bus":
                    if (entity.Bus == null)
                    {
                        entity.Bus = new Bus();
                    }
                    break;
                case "Bike":
                    if (entity.Bike == null)
                    {
                        entity.Bike = new Bike();
                    }
                    break;
            }
        }
    }
}