Class Preference

    Definition

    Namespace:
    Tizen.Applications
    Assembly:
    Tizen.Applications.Preference.dll

    The Preference class provides methods to store and retrieve application specific data/preferences. Preferences are stored in the form of key-value pairs. Key names must be text strings while values can be integers, doubles, strings, or booleans.

    public static class Preference
    Inheritance
    object
    Preference

    Properties

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    Keys

    Retrieves all keys of the application preferences.

    Declaration
    public static IEnumerable<string> Keys { get; }
    Property Value
    Type Description
    System.Collections.Generic.IEnumerable<T><string>

    The list of keys.

    Examples
        Preference.Set("Option_enabled", true);
        Preference.Set("active_user", "Joe");
        Preference.Set("default_volume", 10);
        Preference.Set("brightness", "0.6");
        foreach(string key in Preference.Keys)
        {
            Console.WriteLine("key {0}", key);
        }

    Methods

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    Contains(string)

    Checks whether the given key exists in the preference.

    Declaration
    public static bool Contains(string key)
    Parameters
    Type Name Description
    string key

    The name of the key to check.

    Returns
    Type Description
    bool

    True if the key exists in the preference, otherwise false.

    Remarks

    This method checks if the specified key exists in the preferences. It returns true if the key exists, and false if not. The key argument should be a valid parameter. An ArgumentException will be thrown if the key is invalid. Additionally, an IOException may be thrown if the method fails due to an internal input/output error.

    Examples
        Preference.Set("active_user", "Joe");
        bool exists = Preference.Contains("active_user");
        if (exists)
        {
            string value = Preference.Get<istring>("active_user");
            Console.WriteLine("user {0}", value);
        }
    Exceptions
    Type Condition
    System.ArgumentException

    Thrown if the key is an invalid parameter.

    System.IO.IOException

    Thrown when the method failed due to an internal I/O error.

    View Source

    Get<T>(string)

    Gets the value of a preference item with the specified key. Note that this is a generic method.

    Declaration
    public static T Get<T>(string key)
    Parameters
    Type Name Description
    string key

    The key of the preference.

    Returns
    Type Description
    T

    The value of the preference item if it is of the specified generic type.

    Type Parameters
    Name Description
    T

    The generic type to return.

    Examples
        bool exists = Preference.Contains("active_user");
        if (exists)
        {
            string value = Preference.Get<string>("active_user");
            Console.WriteLine("user {0}", value);
        }
    Exceptions
    Type Condition
    System.Collections.Generic.KeyNotFoundException

    Thrown if the key is not found.

    System.ArgumentException

    Thrown if the key is an invalid parameter.

    System.IO.IOException

    Thrown when the method failed due to an internal I/O error.

    View Source

    GetEventContext(string)

    Gets the event context for the given key.

    Declaration
    public static WeakReference<Preference.EventContext> GetEventContext(string key)
    Parameters
    Type Name Description
    string key

    The preference key.

    Returns
    Type Description
    System.WeakReference<T><Preference.EventContext>

    The event context of respective key.

    Examples
        private static void Preference_PreferenceChanged(object sender, PreferenceChangedEventArgs e)
        {
            Console.WriteLine("key {0}", e.Key);
        }
    
        Preference.EventContext context = null;
        Preference.GetEventContext("active_user").TryGetTarget(out context);
        if(context != null)
        {
            context.Changed += Preference_PreferenceChanged;
        }
    
        Preference.Set("active_user", "Poe");
    
        Preference.GetEventContext("active_user").TryGetTarget(out context);
        if (context != null)
        {
            context.Changed -= Preference_PreferenceChanged;
        }
    Exceptions
    Type Condition
    System.Collections.Generic.KeyNotFoundException

    Thrown if the key is not found.

    System.ArgumentException

    Thrown if the key is invalid parameter.

    See Also
    Preference.EventContext
    View Source

    Remove(string)

    Removes any preference value with the given key.

    Declaration
    public static void Remove(string key)
    Parameters
    Type Name Description
    string key

    The key to remove.

    Examples
        bool exists = Preference.Contains("active_user");
        if (exists)
        {
            string value = Preference.Remove("active_user");
        }
    Exceptions
    Type Condition
    System.Collections.Generic.KeyNotFoundException

    Thrown if the key is not found.

    System.IO.IOException

    Thrown when the method failed due to an internal I/O error.

    View Source

    RemoveAll()

    Removes all the key-value pairs from the preference.

    Declaration
    public static void RemoveAll()
    Examples
        Preference.Set("Option_enabled", true);
        Preference.Set("active_user", "Joe");
        Preference.Set("default_volume", 10);
        Preference.Set("brightness", "0.6");
        Preference.RemoveAll();
    Exceptions
    Type Condition
    System.IO.IOException

    Thrown when the method failed due to an internal I/O error.

    View Source

    Set(string, object)

    Sets a key-value pair representing the preference.

    Declaration
    public static void Set(string key, object value)
    Parameters
    Type Name Description
    string key

    The name of the key to create/modify.

    object value

    The value corresponding to the key.

    Remarks

    If the key already exists in the preference, the old value will be overwritten with a new value. Supported value data types include integers, doubles, strings, and booleans.

    Examples
        Preference.Set("Option_enabled", true);
        Preference.Set("active_user", "Joe");
        Preference.Set("default_volume", 10);
        Preference.Set("brightness", 0.6);
    Exceptions
    Type Condition
    System.ArgumentException

    Thrown if the key is an invalid parameter.

    System.IO.IOException

    Thrown when the method fails due to an internal I/O error.

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