Property Changed Event in LightSwitch 2012

Here we will see how to use the Property Changed Event by developing a LightSwitch Application (Visual C#) in Visual Studio 2012.

The following is the procedure for using the Property Changed Event in LightSwitch 2012.

Step 1

Open the Solution Explorer.



Step 2

In the Solution Explorer, right-click on the Server and choose "Add Table".



Step 3

The table appears.



Step 4

In the table select the "WayOfEntry" field.



Now go to the property window and select "Choice List".



Define the following choices for the property and click the "OK" button.

Step 5

In the Solution Explorer, right-click on the Screens and choose "Add Screen".



Step 6

The Add New Screen dialog box appears. Select "New Data Screen" from the Screen Templates, under screen information, choose "Student" under screen data and provide a name for the screen and click the "OK" button.



Step 7

The Screen Designer appears for the New Data Screen.



From the screen designer select "HighSchoolPercentage" and then go to the property window and uncheck the "Is Visible" checkbox.



Step 8

Now we are going to create a new group for these two fields.



Add the following fields to this group:



Step 9

In the menu bar, select on Write Code a drop down list will appear and from that list select the _created() method and provide the following 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;

using System.ComponentModel;

namespace LightSwitchApplication

{

    public partial class CreateNewStudent

    {

        partial void CreateNewStudent_InitializeDataWorkspace(global::System.Collections.Generic.List<global::Microsoft.LightSwitch.IDataService> saveChangesTo)

        {

            // Write your code here.

            this.StudentProperty = new Student();

        }

        partial void CreateNewStudent_Saved()

        {

            // Write your code here.

            this.Close(false);

            Application.Current.ShowDefaultScreen(this.StudentProperty);

        }

        partial void CreateNewStudent_Created()

        {

            // Write your code here.

            Microsoft.LightSwitch.Threading.Dispatchers.Main.BeginInvoke(() =>

                {

                    ((INotifyPropertyChanged)this.StudentProperty).PropertyChanged += new PropertyChangedEventHandler(CreateNewStudent_propChanged);

                });

        }

        private void CreateNewStudent_propChanged(object sender, PropertyChangedEventArgs e)

        {

            if (e.PropertyName.Equals("WayOfEntry"))

            {

                if (this.StudentProperty.WayOfEntry.Equals("Re"))

                {

                    this.FindControl("HighSchoolPercentage").IsVisible = true;

                    this.FindControl("InterPercentage").IsVisible = false;

                }

                else

                {

                    this.FindControl("HighSchoolPercentage").IsVisible = false;

                    this.FindControl("InterPercentage").IsVisible = true;

                }

            }

        }

    }

}

Step 10

Press F5 to run the application.



As we select the regular option, the HighSchool Percentage control is available.



Similarily, when we select the corresponding option, the Inter Percentage control is available.