Saving the state of multiple checkboxes for wp7 - windows-phone-7

Question

I created a button to create multiple checkbox on no. of clicks for wp7. Below the codes I used for it.
<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
<TextBox x:Name="txtNewTask" HorizontalAlignment="Left" Height="72" TextWrapping="Wrap" VerticalAlignment="Top" Width="328"/>
<Button x:Name="btnAdd" Content="add" HorizontalAlignment="Left" Margin="328,0,0,0" VerticalAlignment="Top" Width="123" Click="btnAdd_Click"/>
<ListBox x:Name="lbToDoList" Margin="0,72,0,0">
<ListBox.ItemTemplate>
<DataTemplate>
<CheckBox Click="CheckBox_Click" Background="{x:Null}">
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding}" Name="tbkTextName" VerticalAlignment="Center" Margin="5,0,5,0" />
</StackPanel>
</CheckBox>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
Now when I exit and re-open my app, I noticed the checkbox’s are unchecked (default state) and its state is not saved. Can you please help me to save the multiple checkbox's value or state?
Can anybody help me to save the multiple checkbox's state. Thanks in advance for your help!

Answer 1

You need to save data to a time when your application is not running. For that staff I use IsolatedStorage. You can save anything, what you need. I found great tutorial, how it implement. hope it's help.

Answer 2

I Think the best way is, to save the value of the checkbox instantly when it changes.
To do so you can do the following:
Assume that the check box in the myPage.xaml looks like:
<CheckBox Content="{Binding Title}" Name="myAutoSavingCheckBox" Click="myAutoSavingCheckBox_Click"/>
In the myPage.xaml.cs you have to define the following method:
private void myAutoSavingCheckBox_Click(object sender, RoutedEventArgs e)
{
App.ViewModel.MyProperty = myAutoSavingCheckBox.IsChecked;
}
The App.ViewModel is declared in the App.xaml.cs:
public partial class App : Application
{
...
public static MainViewModel ViewModel
{
get
{
// Erstellung des Ansichtsmodells verzögern bis erforderlich
if (viewModel == null)
viewModel = new MainViewModel();
return viewModel;
}
}
...
}
Now you define your Property and the saving Function in the MainViewModel.cs as follows:
public class MainViewModel
{
private bool? myProperty;
public bool? MyProperty
{
get
{
return myProperty;
}
set
{
if (value != myProperty)
{
myProperty = value;
SaveSetting("MyProperty", myProperty);
}
}
}
public void SaveSettings(string whatShallBeSavedKey, object whatShallBeSavedValue)
{
if (IsolatedStorageSettings.ApplicationSettings.Contains("whatShallBeSavedKey"))
IsolatedStorageSettings.ApplicationSettings["whatShallBeSavedKey"] = whatShallBeSavedValue;
else
IsolatedStorageSettings.ApplicationSettings.Add("whatShallBeSavedKey", whatShallBeSavedValue);
}
}

Answer 3

Use IsolatedStorage.ApplicationSettings
Here are two helper methods for accessing application settings
/// Get the current value of the setting, or if it is not found, set the
/// setting to the default setting.
protected valueType GetValueOrDefault<valueType>(string Key, valueType defaultValue)
{
valueType value;
object storedValue = null;
try
{
if (_isolatedStore.TryGetValue(Key, out storedValue))
{
value = (valueType)(_isolatedStore[Key] ?? defaultValue);
}
else
{
//the key was not found
value = defaultValue;
}
}
catch (Exception ex)
{
value = defaultValue;
Logger.Error(ex, "Exception while getting IsolatedStorageSettings: ");
}
return value;
}
protected bool AddOrUpdateValue(string Key, Object value)
{
bool valueChanged = false;
object storedValue = null;
try
{
if (_isolatedStore.TryGetValue(Key, out storedValue))
{
if (storedValue != value)
{
_isolatedStore[Key] = value;
valueChanged = true;
}
}
else
{
//the key was not found
_isolatedStore.Add(Key, value);
}
}
catch (Exception ex)
{
Logger.Error(ex, "Exception while adding IsolatedStorageSettings.");
}
return valueChanged;
}
And you can then create a property on some settings class or view model that is backed by IsolatedStorage like this.
string CheckBoxValueKeyName = "checkbox_value";
bool CheckBoxValueDefault = false;
public bool CheckBoxValue
{
get
{
return GetValueOrDefault<bool>(CheckBoxValueKeyName, CheckBoxValueDefault );
}
set
{
AddOrUpdateValue(CheckBoxValueKeyName, value);
}
}
If you don't want to apply the changes of checking the box immediately to isolated storage, the WP7 Tombstone Helper is a quick way to persist the state of your controls after the app tombstones. So, yes, for persistent storage after the application is closed use Isolated Storage.