Application Settings

In This Topic

NOV provides a cross-platform way for NOV applications to store application settings - key/byte array pairs. This is done via the following methods of the static NApplication class:

GetSettingAsync, SetSettingAsync - gets or sets the data for a given key.
RemoveSettingAsync - removes the data for a given key.
GetSettingsNamesAsync - get the names (keys) of all NOV application settings.

Under the hood, NOV saves the application settings to the following location depending on the platform the NOV code is running on:

Windows - app settings are stored in the %AppData% folder, which is the data folder for the current Windows user.
macOS - app settings are stored in the NSUserDefaults.StandardUserDefaults dictionary.
WebAssembly - app settings are stored in the web browser's local storage.

The following example demonstrates a sample NOV DOM node that can be used for application settings:

Sample Application Settings Class	Copy Code
public class MyAppSettings : NNode { public MyAppSettings() { } static MyAppSettings() { MyAppSettingsSchema = NSchema.Create(typeof(MyAppSettings), NNodeSchema); ThemeProperty = MyAppSettingsSchema.AddSlot("Theme", typeof(ENUITheme), ENUITheme.Windows10); DeveloperModeProperty = MyAppSettingsSchema.AddSlot("DeveloperMode", NDomType.Boolean, false); } public ENUITheme Theme { get { return (ENUITheme)GetValue(ThemeProperty); } set { SetValue(ThemeProperty, value); } } public bool DeveloperMode { get { return (bool)GetValue(DeveloperModeProperty); } set { SetValue(DeveloperModeProperty, value); } } public static readonly NSchema MyAppSettingsSchema; public static readonly NProperty ThemeProperty; public static readonly NProperty DeveloperModeProperty; }

Sample Application Settings Class

Copy Code

public class MyAppSettings : NNode
{
    public MyAppSettings()
    {
    }
    static MyAppSettings()
    {
        MyAppSettingsSchema = NSchema.Create(typeof(MyAppSettings), NNodeSchema);
        ThemeProperty = MyAppSettingsSchema.AddSlot("Theme", typeof(ENUITheme), ENUITheme.Windows10);
        DeveloperModeProperty = MyAppSettingsSchema.AddSlot("DeveloperMode", NDomType.Boolean, false);
    }

    public ENUITheme Theme
    {
        get
        {
            return (ENUITheme)GetValue(ThemeProperty);
        }
        set
        {
            SetValue(ThemeProperty, value);
        }
    }
    public bool DeveloperMode
    {
        get
        {
            return (bool)GetValue(DeveloperModeProperty);
        }
        set
        {
            SetValue(DeveloperModeProperty, value);
        }
    }

    public static readonly NSchema MyAppSettingsSchema;
    public static readonly NProperty ThemeProperty;
    public static readonly NProperty DeveloperModeProperty;
}

You can use the following code to save and load the application settings:

Saving and Loading Application Settings	Copy Code
private void SaveSettingsButton_Click(NEventArgs arg) { using (MemoryStream stream = new MemoryStream()) { // Use a DOM node serializer to save the app settings to a memory stream NDomNodeSerializer serializer = new NDomNodeSerializer(); serializer.SaveToStream(m_AppSettings, stream, SettingsFormat); // Save the settings data byte[] settingsData = stream.ToArray(); NApplication.SetSettingAsync(AppSettingsKey, settingsData).Then( delegate (NUndefined ud) { // Settings saved successfully } ); } } private void LoadSettingsButton_Click(NEventArgs arg) { // Load the settings data NApplication.GetSettingAsync(AppSettingsKey).Then( delegate (byte[] settingsData) { using (MemoryStream stream = new MemoryStream(settingsData)) { // Use a DOM node deserializer to load the app settings from the memory stream NDomNodeDeserializer deserializer = new NDomNodeDeserializer(); MyAppSettings loadedSettings = (MyAppSettings)deserializer.LoadFromStream(stream, SettingsFormat)[0]; } }, delegate (Exception ex) { NMessageBox.ShowError("Failed to load the app settings. Exception was: " + ex.Message, "Error"); } ); }

Saving and Loading Application Settings

Copy Code

private void SaveSettingsButton_Click(NEventArgs arg)
{
    using (MemoryStream stream = new MemoryStream())
    {
        // Use a DOM node serializer to save the app settings to a memory stream
        NDomNodeSerializer serializer = new NDomNodeSerializer();
        serializer.SaveToStream(m_AppSettings, stream, SettingsFormat);
        // Save the settings data
        byte[] settingsData = stream.ToArray();
        NApplication.SetSettingAsync(AppSettingsKey, settingsData).Then(
            delegate (NUndefined ud)
            {
                // Settings saved successfully
            }
        );
    }
}

private void LoadSettingsButton_Click(NEventArgs arg)
{
    // Load the settings data
    NApplication.GetSettingAsync(AppSettingsKey).Then(
        delegate (byte[] settingsData)
        {
            using (MemoryStream stream = new MemoryStream(settingsData))
            {
                // Use a DOM node deserializer to load the app settings from the memory stream
                NDomNodeDeserializer deserializer = new NDomNodeDeserializer();
                MyAppSettings loadedSettings = (MyAppSettings)deserializer.LoadFromStream(stream, SettingsFormat)[0];
            }
        },
        delegate (Exception ex)
        {
            NMessageBox.ShowError("Failed to load the app settings. Exception was: " + ex.Message, "Error");
        }
    );
}

You can always store your application's settings in any other way, but if you plan to release your NOV application to other platforms, too, then we strongly recommend you use the NOV application settings mechanism. This will save you a lot of work in the future.

Serialization

DOM Serialization