How do I update image source in my data template long list selector WP8?

[Mankuji]

Update Image source in data template long list selector WP8

My problem is : In my long list selector, when my list items loaded and i click on edit button to activate/inactive items

When i active / d-activate the top items then on scrolling down long list selector the some- where middle items where automatically got selected.

Please suggest something to me to get rid of this issue:

MainPage.xaml

sing System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Navigation;
using Microsoft.Phone.Controls;
using Microsoft.Phone.Shell;
using longlistselector.Resources;
using System.Windows.Media.Imaging;
using System.Collections.ObjectModel;

namespace longlistselector
{
public partial class MainPage : PhoneApplicationPage
{
// Constructor
List<GroupClass> List = new List<GroupClass>();
ObservableCollection<GroupClass> DataList = null;
static bool IsEditable = false;
public MainPage()
{
InitializeComponent();

// Sample code to localize the ApplicationBar
//BuildLocalizedApplicationBar();

List.Add(new GroupClass() { Name = "Temp", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 1 });
List.Add(new GroupClass() { Name = "Temp1", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 2 });
List.Add(new GroupClass() { Name = "Temp2", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 3 });
List.Add(new GroupClass() { Name = "Temp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 4 });
List.Add(new GroupClass() { Name = "Aemp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 5 });
List.Add(new GroupClass() { Name = "Aemp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 6 });
List.Add(new GroupClass() { Name = "Aemp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 7 });
List.Add(new GroupClass() { Name = "Bemp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 8 });
List.Add(new GroupClass() { Name = "Bemp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 9 });
List.Add(new GroupClass() { Name = "Bemp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 10 });
List.Add(new GroupClass() { Name = "Cemp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 11 });
List.Add(new GroupClass() { Name = "Cemp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 12 });
List.Add(new GroupClass() { Name = "Cemp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 13 });
List.Add(new GroupClass() { Name = "Demp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 14 });
List.Add(new GroupClass() { Name = "Demp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 15 });
List.Add(new GroupClass() { Name = "Demp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 16 });
List.Add(new GroupClass() { Name = "Eemp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 17 });
List.Add(new GroupClass() { Name = "Eemp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 18 });
List.Add(new GroupClass() { Name = "Eemp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 19 });
List.Add(new GroupClass() { Name = "Eemp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 20 });
List.Add(new GroupClass() { Name = "Femp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 21 });
List.Add(new GroupClass() { Name = "Femp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 22 });
List.Add(new GroupClass() { Name = "Gemp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 23 });
List.Add(new GroupClass() { Name = "Gemp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 24 });
List.Add(new GroupClass() { Name = "Hemp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 25 });
List.Add(new GroupClass() { Name = "Hemp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 26 });
List.Add(new GroupClass() { Name = "Jemp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 27 });
List.Add(new GroupClass() { Name = "Jemp3", IsActive = false, IsCustom = false, IsEditable = false, UnitGroupID = 28 });

DataList = new ObservableCollection<GroupClass>(List);
this.GroupListBox.ItemsSource = DataList;

}

private void ActiveInactiveImage_Tap_1(object sender, System.Windows.Input.GestureEventArgs e)
{

Image imgobj = sender as Image;
GroupClass gcobj = (GroupClass)imgobj.DataContext;
if (gcobj != null)
{
gcobj.IsActive = !gcobj.IsActive;

imgobj.DataContext = gcobj;

DataList.FirstOrDefault(x => x.UnitGroupID == gcobj.UnitGroupID).IsActive = gcobj.IsActive;

imgobj.Source = new BitmapImage(new Uri(gcobj.IsActive ? "/Assets/Images/Active.png" : "/Assets/Images/Inactive.png", UriKind.Relative));

}

GroupListBox.ItemsSource = DataList;
}

private void ApplicationBarIconButton_Click_1(object sender, EventArgs e)
{
IsEditable = !IsEditable;
foreach (var obj in DataList)
{
obj.IsEditable = IsEditable; obj.IsChecked = false;

}
this.GroupListBox.ItemsSource = null;
this.GroupListBox.ItemsSource = DataList;

}
}
}

GroupClass.cs :

sing System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;

namespace longlistselector
{
class GroupClass
{

public string ImageSource
{
get;
set;
}
public string Content
{
get { return IsActive ? "/Assets/Images/Active.png" : "/Assets/Images/Inactive.png"; }

}
public string Name
{
get;
set;
}
public long UnitGroupID
{
get;
set;
}
public bool IsActive
{
get;

set;

}

public bool IsCustom
{
get;
set;
}
public bool IsChecked
{
get;
set;
}
public bool IsEditable
{
get
;
set;

}

public Visibility ControlVisibility
{
get { return IsEditable? Visibility.Visible : Visibility.Collapsed; }
}

}
}