Class Preference

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Definition

Namespace:
Tizen.Applications
Assembly:
Tizen.Applications.Preference.dll
API Level:
3

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.


                
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public static class Preference
Inheritance
System.Object
Preference

Properties

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Keys

Retrieves all keys of the application preferences.

Declaration

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

The list of keys.
Examples

                

                

                    
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    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

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Contains(String)

Checks whether the given key exists in the preference.

Declaration

                
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public static bool Contains(string key)
Parameters
Type Name Description
System.String key

The name of the key to check.
Returns
Type Description
Boolean

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

                

                

                    
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    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.
IOException

Thrown when the method failed due to an internal I/O error.
API Level: 3
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Get<T>(String)

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

Declaration

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

                

                

                    
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    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.
System.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
View Source

GetEventContext(String)

Gets the event context for the given key.

Declaration

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

The preference key.
Returns
Type Description
WeakReference<Preference.EventContext>

The event context of respective key.
Examples

                

                

                    
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    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.
System.ArgumentException

Thrown if the key is invalid parameter.
See Also
API Level: 3
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Remove(String)

Removes any preference value with the given key.

Declaration

                
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public static void Remove(string key)
Parameters
Type Name Description
System.String key

The key to remove.
Examples

                

                

                    
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    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
View Source

RemoveAll()

Removes all the key-value pairs from the preference.

Declaration

                
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public static void RemoveAll()
Examples

                

                

                    
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    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
View Source

Set(String, Object)

Sets a key-value pair representing the preference.

Declaration

                
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public static void Set(string key, object value)
Parameters
Type Name Description
System.String key

The name of the key to create/modify.
System.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

                

                

                    
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    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.
IOException

Thrown when the method failed due to an internal I/O error.
API Level: 3