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

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

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.

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.

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

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.

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.

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.