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我想爲我的Windows Phone 7應用程序創建一個設置頁面，我使用本文爲基礎http://msdn.microsoft.com/en-us/library/ff769510(v=vs.92).aspx所以我的應用程序類是：有什麼辦法可以知道IsolatedStorageSettings.ApplicationSettings中的變量何時更改？
public class AppSettings
{
// Our isolated storage settings
IsolatedStorageSettings isolatedStore;
// The isolated storage 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 AppSettings()
{
try
{
// Get the settings for this application.
isolatedStore = IsolatedStorageSettings.ApplicationSettings;
}
catch (Exception e)
{
Debug.WriteLine("Exception while using IsolatedStorageSettings: " + 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 (isolatedStore.Contains(Key))
{
// If the value has changed
if (isolatedStore[Key] != value)
{
// Store the new value
isolatedStore[Key] = value;
valueChanged = true;
}
}
// Otherwise create the key.
else
{
isolatedStore.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="valueType"></typeparam>
/// <param name="Key"></param>
/// <param name="defaultValue"></param>
/// <returns></returns>
public valueType GetValueOrDefault<valueType>(string Key, valueType defaultValue)
{
valueType value;
// If the key exists, retrieve the value.
if (isolatedStore.Contains(Key))
{
value = (valueType)isolatedStore[Key];
}
// Otherwise, use the default value.
else
{
value = defaultValue;
}
return value;
}
/// <summary>
/// Save the settings.
/// </summary>
public void Save()
{
isolatedStore.Save();
}
/// <summary>
/// Property to get and set a CheckBox Setting Key.
/// </summary>
public bool CheckBoxSetting
{
get
{
return GetValueOrDefault<bool>(CheckBoxSettingKeyName, CheckBoxSettingDefault);
}
set
{
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
{
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
{
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
{
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
{
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
{
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
{
AddOrUpdateValue(PasswordSettingKeyName, value);
Save();
}
}
}
一切正常，我能更新從XAML設置頁面設置值，我可以使用
IsolatedStorageSettings Settings;
Settings = IsolatedStorageSettings.ApplicationSettings;
string checkboxvalue = (string)Settings["CheckBoxSetting"];
現在我想做的事，我的主要應用程序訪問的設置值是能夠知道當應用程序中設置的值改變/更新，從而使當設置更新時，我可以執行操作。
本質上，問題是：**有什麼辦法可以知道IsolatedStorageSettings.ApplicationSettings中的變量何時發生變化？** – rajat