使用类绑定设置（Windows Phone）

Question

I'm new to WP development and I have a problem I can't get fixed on my own. I'm trying to set up a settings page. I copied most of it from that msdn article:

http://msdn.microsoft.com/en-us/library/windowsphone/develop/ff769510(v=vs.105).aspx#BKMK_CreatingaSettingsPageThatDoesNotRequireaConfirmationButton

The problem is connected to this line:

<phone:PhoneApplicationPage.Resources>
  <local:Page1 x:Key="appSettings" />
</phone:PhoneApplicationPage.Resources>

It behaves completly random. Most of the time VS just crashes. I am sure that this is because VS tries to connect to the IsolatedStorage. But the Emulator just closes the App when I try to access the page.

The full code of the settings page (Page1):
Page1.xaml:

    <phone:PhoneApplicationPage 
    x:Class="MyApp.Page1"
    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"

    xmlns:local="clr-namespace:MyApp"
    FontFamily="{StaticResource PhoneFontFamilyNormal}"
    FontSize="{StaticResource PhoneFontSizeNormal}"
    Foreground="{StaticResource PhoneForegroundBrush}"
    SupportedOrientations="Portrait" Orientation="Portrait"
    mc:Ignorable="d" d:DesignHeight="768" d:DesignWidth="480"
    shell:SystemTray.IsVisible="True">

    <phone:PhoneApplicationPage.Resources>
      <local:Page1 x:Key="appSettings" />
    </phone:PhoneApplicationPage.Resources>


        <!--LayoutRoot is the root grid where all page content is placed-->

        <Grid x:Name="LayoutRoot" Background="Transparent">
            <Grid.RowDefinitions>
                <RowDefinition Height="Auto"/>
                <RowDefinition Height="*"/>
            </Grid.RowDefinitions>

            <!--TitlePanel contains the name of the application and page title-->
            <StackPanel x:Name="TitlePanel" Grid.Row="0" Margin="12,17,0,28">
                <TextBlock x:Name="ApplicationTitle" Text="MYAPP" Style="{StaticResource PhoneTextNormalStyle}"/>
                <TextBlock x:Name="PageTitle" Text="settings" Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}"/>
            </StackPanel>
        <Grid x:Name="ContentGrid" Grid.Row="1">
            <CheckBox Content="CheckBox Setting" Height="Auto" HorizontalAlignment="Left" Margin="60,20,0,0" Name="checkBoxSetting" VerticalAlignment="Top"
            IsChecked="{Binding Source={StaticResource appSettings}, Path=CheckBoxSetting, Mode=TwoWay}"  />

            <ListBox Height="140" HorizontalAlignment="Left" Margin="70,150,0,0" Name="listBoxSetting" 
        VerticalAlignment="Top" Width="360"  SelectedIndex="{Binding Source={StaticResource appSettings}, Path=ListBoxSetting, Mode=TwoWay}">

                <ListBoxItem Content="Times New Roman" FontSize="24" FontFamily="Times New Roman" />
                <ListBoxItem Content="Arial" FontSize="24" FontFamily="Arial" />
                <ListBoxItem Content="Comic Sans MS" FontSize="24" FontFamily="Comic Sans MS" />
            </ListBox>

            <RadioButton Content="Choice One" Height="Auto" HorizontalAlignment="Left" Margin="60,0,0,235" Name="radioButton1" VerticalAlignment="Bottom" GroupName="GroupOne" IsChecked="{Binding Source={StaticResource appSettings}, Path=RadioButton1Setting, Mode=TwoWay}" />
            <RadioButton Content="Choice Two" Height="Auto" HorizontalAlignment="Left" Margin="60,350,0,0" Name="radioButton2" VerticalAlignment="Top" GroupName="GroupOne" IsChecked="{Binding Source={StaticResource appSettings}, Path=RadioButton2Setting, Mode=TwoWay}"/>
            <RadioButton Content="Choice Three" Height="Auto" HorizontalAlignment="Left" Margin="60,400,0,0" Name="radioButton3" VerticalAlignment="Top" GroupName="GroupOne" IsChecked="{Binding Source={StaticResource appSettings}, Path=RadioButton3Setting, Mode=TwoWay}"/>
        </Grid>

    </Grid>



</phone:PhoneApplicationPage>

And the Page1.xaml.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;
using System.Diagnostics;



namespace Schedule
{
    public partial class Page1 : PhoneApplicationPage
    {
        // Our settings
        IsolatedStorageSettings settings;

        // The key names of our settings
        const string CheckBoxSettingKeyName = "CheckBoxSetting";
        const string ListBoxSettingKeyName = "ListBoxSetting";
        const string RadioButton1SettingKeyName = "RadioButton1Setting";
        const string RadioButton2SettingKeyName = "RadioButton2Setting";
        const string RadioButton3SettingKeyName = "RadioButton3Setting";
        const string UsernameSettingKeyName = "UsernameSetting";
        const string PasswordSettingKeyName = "PasswordSetting";

        // The default value of our settings
        const bool CheckBoxSettingDefault = true;
        const int ListBoxSettingDefault = 0;
        const bool RadioButton1SettingDefault = true;
        const bool RadioButton2SettingDefault = false;
        const bool RadioButton3SettingDefault = false;
        const string UsernameSettingDefault = "";
        const string PasswordSettingDefault = "";

        /// <summary>
        /// Constructor that gets the application settings.
        /// </summary>
        public Page1()
        {
            InitializeComponent();

            // Get the settings for this application.
            try
            {


                    settings = IsolatedStorageSettings.ApplicationSettings;


            }
            catch(System.IO.IsolatedStorage.IsolatedStorageException e)
            {
                MessageBox.Show(e.ToString());
            }

        }

        /// <summary>
        /// Update a setting value for our application. If the setting does not
        /// exist, then add the setting.
        /// </summary>
        /// <param name="Key"></param>
        /// <param name="value"></param>
        /// <returns></returns>
        public bool AddOrUpdateValue(string Key, Object value)
        {
            bool valueChanged = false;

            // If the key exists
            if (settings.Contains(Key))
            {
                // If the value has changed
                if (settings[Key] != value)
                {
                    // Store the new value
                    settings[Key] = value;
                    valueChanged = true;
                }
            }
            // Otherwise create the key.
            else
            {
                settings.Add(Key, value);
                valueChanged = true;
            }
           return valueChanged;
        }

        /// <summary>
        /// Get the current value of the setting, or if it is not found, set the 
        /// setting to the default setting.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="Key"></param>
        /// <param name="defaultValue"></param>
        /// <returns></returns>
        public T GetValueOrDefault<T>(string Key, T defaultValue)
        {
            T value;

            // If the key exists, retrieve the value.
            if (settings.Contains(Key))
            {
                value = (T)settings[Key];
            }
            // Otherwise, use the default value.
            else
            {
                value = defaultValue;
            }
            return value;
        }

        /// <summary>
        /// Save the settings.
        /// </summary>
        public void Save()
        {
            settings.Save();
        }


        /// <summary>
        /// Property to get and set a CheckBox Setting Key.
        /// </summary>
        public bool CheckBoxSetting
        {
            get
            {
                return GetValueOrDefault<bool>(CheckBoxSettingKeyName, CheckBoxSettingDefault);
            }
            set
            {
                if (AddOrUpdateValue(CheckBoxSettingKeyName, value))
                {
                    Save();
                }
            }
        }


        /// <summary>
        /// Property to get and set a ListBox Setting Key.
        /// </summary>
        public int ListBoxSetting
        {
            get
            {
                return GetValueOrDefault<int>(ListBoxSettingKeyName, ListBoxSettingDefault);
            }
            set
            {
                if (AddOrUpdateValue(ListBoxSettingKeyName, value))
                {
                   Save();
                }
            }
        }


        /// <summary>
        /// Property to get and set a RadioButton Setting Key.
        /// </summary>
        public bool RadioButton1Setting
        {
            get
            {
                return GetValueOrDefault<bool>(RadioButton1SettingKeyName, RadioButton1SettingDefault);
            }
            set
            {
                if (AddOrUpdateValue(RadioButton1SettingKeyName, value))
                {    
                    Save();
                }
            }
        }


        /// <summary>
        /// Property to get and set a RadioButton Setting Key.
        /// </summary>
        public bool RadioButton2Setting
        {
            get
            {
                return GetValueOrDefault<bool>(RadioButton2SettingKeyName, RadioButton2SettingDefault);
            }
            set
            {
                if (AddOrUpdateValue(RadioButton2SettingKeyName, value))
                {
                    Save();
                }
            }
        }

        /// <summary>
        /// Property to get and set a RadioButton Setting Key.
        /// </summary>
        public bool RadioButton3Setting
        {
            get
            {
                return GetValueOrDefault<bool>(RadioButton3SettingKeyName, RadioButton3SettingDefault);
            }
            set
            {
                if (AddOrUpdateValue(RadioButton3SettingKeyName, value))
                {
                    Save();
                }
            }
        }

        /// <summary>
        /// Property to get and set a Username Setting Key.
        /// </summary>
        public string UsernameSetting
        {
            get
            {
                return GetValueOrDefault<string>(UsernameSettingKeyName, UsernameSettingDefault);
            }
            set
            {
                if (AddOrUpdateValue(UsernameSettingKeyName, value))
                {
                    Save();
                }
            }
        }

        /// <summary>
        /// Property to get and set a Password Setting Key.
        /// </summary>
        public string PasswordSetting
        {
            get
            {
                return GetValueOrDefault<string>(PasswordSettingKeyName, PasswordSettingDefault);
            }
            set
            {
                if (AddOrUpdateValue(PasswordSettingKeyName, value))
                {
                    Save();
                }
            }

    }
    }
}

Am I would be very happy about any help. Thanks.

Answer 1

Instead of local:Page1 , you're supposed to put a separate class (named AppSettings in the MSDN sample).

In your case, you have put an instance of Page1 in the XAML of... Page1! Therefore, when the runtime creates Page1, it parses the XAML, find this line of code, create the new Page1 instance, which will in turn create a Page1 instance, and so on...