Save and load settings in a UWP app

Article
10/20/2022

This topic covers what you need to know to get started loading, and saving, settings in a Universal Windows Platform (UWP) app. The main APIs are introduced, and links are provided to help you learn more.

Use settings to remember the user-customizable aspects of your app. For example, a news reader could use app settings to save which news sources to display and what font to use for reading articles.

We’ll look at code to save and load app settings.

What do you need to know

Use app settings to store configuration data such as user preferences and app state.

The following data types can be used with settings: integers, doubles, floats, chars, strings, Points, DateTimes, and more. You can also store instances of the ApplicationDataCompositeValue class which is useful when there are multiple settings that should be treated as a unit. For example, a font name and point size for displaying text in the reading pane of your app should be saved/restored as a single unit. This prevents one setting from getting out of sync with the other due to concurrent access, such as between the main program and a background task.

Here are the main APIs you need to know about to save or load app settings:

Windows.Storage.ApplicationData.Current.LocalSettings gets the application settings container from the local app data store. Settings stored here are kept on the device.
Windows.Storage.ApplicationData.Current.RoamingSettings gets the application settings container from the roaming app data store. Settings stored here no longer roam (as of Windows 11), but the settings store is still available. The recommended replacement for RoamingSettings is Azure App Service. Azure App Service is widely supported, well documented, reliable, and supports cross-platform/cross-ecosystem scenarios such as iOS, Android and web.
Windows.Storage.ApplicationDataContainer is a container that represents app settings as key/value pairs. Use this class to create and retrieve setting values.
Windows.Storage.ApplicationDataCompositeValue represents multiple app settings that should be serialized as a unit. This is useful when one setting shouldn't be updated independently of another.

Save app settings

For this introduction, we will focus on two simple scenarios: saving and loading a simple app setting, and saving and loading a composite font/font size setting.

ApplicationDataContainer localSettings = Windows.Storage.ApplicationData.Current.LocalSettings;

// Save a setting locally on the device
localSettings.Values["test setting"] = "a device specific setting";

// Save a composite setting locally on the device
Windows.Storage.ApplicationDataCompositeValue composite = new Windows.Storage.ApplicationDataCompositeValue();
composite["Font"] = "Calibri";
composite["FontSize"] = 11;
localSettings.Values["FontInfo"] = composite;

Save a setting by first getting an ApplicationDataContainer for the local settings data store with Windows.Storage.ApplicationData.Current.LocalSettings. Key/value dictionary pairs that you assign to this instance are saved in the local device setting data store.

In the code snippet above, an ApplicationDataCompositeValue stores multiple key/value pairs. Composite values are useful when you have multiple settings that shouldn't get out of sync with each other. When you save a ApplicationDataCompositeValue, the values are saved and loaded as a unit, or atomically. This way settings that are related won't get out of sync.

Load app settings

ApplicationDataContainer localSettings = Windows.Storage.ApplicationData.Current.LocalSettings;

// load a setting that is local to the device
String localValue = localSettings.Values["test setting"] as string;

// load a composite setting
Windows.Storage.ApplicationDataCompositeValue composite = (ApplicationDataCompositeValue)localSettings.Values["FontInfo"];
if (composite != null)
{
    String fontName = composite["Font"] as string;
    int fontSize = (int)composite["FontSize"];
}

Load a setting by first getting an ApplicationDataContainer instance for the local settings data store with Windows.Storage.ApplicationData.Current.LocalSettings. Then use it to retrieve key/value pairs. If the data is not present, you'll get a null object. In C#, this means that the localValue will be null if the setting does not exist.

Load a composite setting by following a similar pattern. Access key/value pairs from the local settings data store. If the data is not present, you'll get a null ApplicationDataContainer. That's why there is a if (composite != null) check in the example code above.

Useful APIs and docs

Here is a quick summary of APIs, and other useful documentation, to help get you started saving and loading app settings.

Useful APIs

API	Description
ApplicationData.LocalSettings	Gets the application settings container from the local app data store.
ApplicationData.RoamingSettings	Gets the application settings container from the roaming app data store.
ApplicationDataContainer	A container for app settings that supports creating, deleting, enumerating, and traversing the container hierarchy.
Windows.UI.ApplicationSettings Namespace	Provides classes that you'll use to define the app settings that appear in the settings pane of the Windows shell.

Useful docs

Topic	Description
Guidelines for app settings	Describes best practices for creating and displaying app settings.
Store and retrieve settings and other app data	Walk-through for saving and retrieving settings.

Useful code samples

Code sample	Description
Application data sample	Scenarios 2-4 focus on settings

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