漫谈windows phone 7 独立存储（二）

在上篇文章中，我们谈了IsolatedStorageFile，今天我们来看一下IsolatedStorageSettings的用法。

IsolatedStorageSettings可以说是保存数据到独立存储最简单的方式，如果是键值对的数据类型，并想要持久地保存在独立存储中，这时就可以使用IsolatedStorageSettings。

当退出应用时，应用的配置内容会自动序列化至独立存储中的一个文件内，当应用launched或者activated时，又会使用先前的数据来填充字典。

在本例中，我们将对IsolatedStorageSettings进行CRUD操作。

XAML:

<phone:PhoneApplicationPage 
    x:Class="IsolatedStorageSettingsDemo.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone" 
    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone" 
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
    FontFamily="{StaticResource PhoneFontFamilyNormal}" 
    FontSize="{StaticResource PhoneFontSizeNormal}" 
    Foreground="{StaticResource PhoneForegroundBrush}" 
    SupportedOrientations="Portrait" Orientation="Portrait" 
    mc:Ignorable="d" d:DesignWidth="480" d:DesignHeight="768" 
    shell:SystemTray.IsVisible="True">
    
    <Grid x:Name="LayoutRoot" Background="{StaticResource PhoneBackgroundBrush}">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
        <!--TitleGrid is the name of the application and page title-->
        <Grid x:Name="TitleGrid" Grid.Row="0">
            <TextBlock Text="Isolated Storage Settings Demo"  
                       x:Name="textBlockListTitle"  
                       Style="{StaticResource PhoneTextTitle1Style}"  
                       FontSize="30" />
        </Grid>
        <!--ContentGrid is empty. Place new content here-->
        <Grid x:Name="ContentGrid" Grid.Row="1">
            <TextBox Height="72" HorizontalAlignment="Left"  
                     Margin="172,46,0,0" Name="txtKey" Text=""  
                     VerticalAlignment="Top" Width="212" />
            <Button Content="Save" Height="70"  
                    HorizontalAlignment="Left" Margin="78,228,0,0"  
                    Name="btnSave" VerticalAlignment="Top" Width="160"  
                    Click="btnSave_Click" />
            <ListBox Height="168" HorizontalAlignment="Left" Margin="94,392,0,0"  
                     Name="lstKeys" VerticalAlignment="Top" Width="274"  
                     BorderThickness="1" SelectionChanged="lstKeys_SelectionChanged" />
            <TextBlock Height="39" HorizontalAlignment="Left" Margin="94,62,0,0"  
                       Name="textBlock1" Text="Key" VerticalAlignment="Top" />
            <TextBox Height="74" HorizontalAlignment="Left" Margin="172,124,0,0"  
                     Name="txtValue" Text="" VerticalAlignment="Top" Width="212" />
            <TextBlock Height="39" HorizontalAlignment="Left" Margin="94,140,0,0"  
                       Name="textBlock2" Text="Value" VerticalAlignment="Top" />
            <Button Content="Delete" Height="70" HorizontalAlignment="Left"  
                    Margin="224,228,0,0" Name="btnDelete" VerticalAlignment="Top"  
                    Width="160" Click="btnDelete_Click" />
            <TextBlock Height="39" HorizontalAlignment="Left" Margin="94,347,0,0"  
                       Name="textBlock3" Text="List of Keys" VerticalAlignment="Top" />
        </Grid>
    </Grid>
</phone:PhoneApplicationPage>

CS:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using Microsoft.Phone.Controls;
using System.IO.IsolatedStorage;

namespace IsolatedStorageSettingsDemo
{
    public partial class MainPage : PhoneApplicationPage
    {
        private IsolatedStorageSettings _appSetting;
        // Constructor
        public MainPage()
        {
            InitializeComponent();
            SupportedOrientations = SupportedPageOrientation.Portrait;
            _appSetting = IsolatedStorageSettings.ApplicationSettings;
        }

        private void btnSave_Click(object sender, RoutedEventArgs e)
        {
            if (!string.IsNullOrEmpty(txtKey.Text))
            {
                if (_appSetting.Contains(txtKey.Text))
                {
                    _appSetting[txtKey.Text] = txtValue.Text;
                }
                else
                {
                    _appSetting.Add(txtKey.Text, txtValue.Text);
                }
                _appSetting.Save();
                BindKeyList();
            }
        }

        private void btnDelete_Click(object sender, RoutedEventArgs e)
        {
            if (lstKeys.SelectedIndex > -1)
            {
                _appSetting.Remove(lstKeys.SelectedItem.ToString());
                _appSetting.Save();
                BindKeyList();
            }
        }

        private void BindKeyList()
        {
            lstKeys.Items.Clear();
            foreach (string key in _appSetting.Keys)
            {
                lstKeys.Items.Add(key);
            }
            txtKey.Text = "";
            txtValue.Text = "";
        }

        private void lstKeys_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            if (e.AddedItems.Count > 0)
            {
                string key = e.AddedItems[0].ToString();
                if (_appSetting.Contains(key))
                {
                    txtKey.Text = key;
                    txtValue.Text = _appSetting[key].ToString();
                }
            }
        }
    }
}

效果图：