Class Preference

The preference class provides APIs to store and retrieve an application specific data/preference. A preference is saved in the form of a key-value pair. Keys are always text strings and the value can be any one of the four types: integer, double, string, and boolean.

Inheritance

Object

Preference

Inherited Members

Object.Equals(Object)

Object.Equals(Object, Object)

Object.GetHashCode()

Object.GetType()

Object.MemberwiseClone()

Object.ReferenceEquals(Object, Object)

Object.ToString()

Namespace: Tizen.Applications

Assembly: Tizen.Applications.Preference.dll

API Level: 3

Syntax

public static class Preference

Properties

Keys

Retrieves all keys of the application preferences.

Declaration

public static IEnumerable<string> Keys { get; }

Property Value

Type	Description
IEnumerable<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);
    }

API Level: 3

Methods

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

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
ArgumentException	Thrown if the key is an invalid parameter.
IOException	Thrown when the method failed due to an internal I/O error.

API Level: 3

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
KeyNotFoundException	Thrown if the key is not found.
ArgumentException	Thrown if the key is an invalid parameter.
IOException	Thrown when the method failed due to an internal I/O error.

API Level: 3

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
WeakReference<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
KeyNotFoundException	Thrown if the key is not found.
ArgumentException	Thrown if the key is invalid parameter.

See Also

Preference.EventContext

API Level: 3

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
KeyNotFoundException	Thrown if the key is not found.
IOException	Thrown when the method failed due to an internal I/O error.

API Level: 3

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

API Level: 3

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. Data types for supported values are: integer, double, string, and bool.

Examples

    Preference.Set("Option_enabled", true);
    Preference.Set("active_user", "Joe");
    Preference.Set("default_volume", 10);
    Preference.Set("brightness", "0.6");

Exceptions

Type	Condition
ArgumentException	Thrown if the key is an invalid parameter.
IOException	Thrown when the method failed due to an internal I/O error.

API Level: 3