c# - approach for saving user settings in a WPF application?

Question

What approach do you recommend for persisting user settings in a WPF windows (desktop) application? Note that the idea is that the user can change their settings at run time, and then can close down the application, then when starting up the application later the application will use the current settings. Effectively then it will appear as if the application settings do not change.

Q1 - Database or other approach? I do have a sqlite database that I will be using anyway hence using a table in the database would be as good as any approach?

Q2 - If Database: What database table design? One table with columns for different data types that one might have (e.g. string, long, datetime etc) OR just a table with a string for the value upon which you have to serialize and de-serialize the values? I'm thinking the first would be easier, and if there aren't many settings the overhead isn't much?

Q3 - Could Application Settings be used for this? If so are there any special tasks required to enable the persistance here? Also what would happen re usage of the "default" value in the Application Settings designer in this case? Would the default override any settings that were saved between running the application? (or would you need to NOT use the default value)

Answer 1

Apart from Database, you can also have following options to save user related settings

1) registry under HKEY_CURRENT_USER

2) in a file in AppData folder

3) using Settings file in WPF and by setting its scope as User

Answer 2

You can use project settings for this, using database is not the best option considering the time consumed to read and write the settings(specially if you use web services).

Here are few links which explains how to achieve this -

http://blogs.msdn.com/b/patrickdanino/archive/2008/07/23/user-settings-in-wpf.aspx

http://khason.net/blog/quick-wpf-tip-how-to-bind-to-wpf-application-resources-and-settings/

http://joshsmithonwpf.wordpress.com/2007/12/27/a-configurable-window-for-wpf/

Answer 3

The long running most typical approach to this question is: Isolated Storage.

Serialize your control state to XML or some other format (especially easily if you're saving Dependency Properties with WPF), then save the file to the user's isolated storage.

If you do want to go the app setting route, I tried something similar at one point myself...though the below approach could easily be adapted to use Isolated Storage:

class SettingsManager
{
    public static void LoadSettings(FrameworkElement sender, Dictionary<FrameworkElement, DependencyProperty> savedElements)
    {
        EnsureProperties(sender, savedElements);
        foreach (FrameworkElement element in savedElements.Keys)
        {
            try
            {
                element.SetValue(savedElements[element], Properties.Settings.Default[sender.Name + "." + element.Name]);
            }
            catch (Exception ex) { }
        }
    }

    public static void SaveSettings(FrameworkElement sender, Dictionary<FrameworkElement, DependencyProperty> savedElements)
    {
        EnsureProperties(sender, savedElements);
        foreach (FrameworkElement element in savedElements.Keys)
        {
            Properties.Settings.Default[sender.Name + "." + element.Name] = element.GetValue(savedElements[element]);
        }
        Properties.Settings.Default.Save();
    }

    public static void EnsureProperties(FrameworkElement sender, Dictionary<FrameworkElement, DependencyProperty> savedElements)
    {
        foreach (FrameworkElement element in savedElements.Keys)
        {
            bool hasProperty =
                Properties.Settings.Default.Properties[sender.Name + "." + element.Name] != null;

            if (!hasProperty)
            {
                SettingsAttributeDictionary attributes = new SettingsAttributeDictionary();
                UserScopedSettingAttribute attribute = new UserScopedSettingAttribute();
                attributes.Add(attribute.GetType(), attribute);

                SettingsProperty property = new SettingsProperty(sender.Name + "." + element.Name,
                    savedElements[element].DefaultMetadata.DefaultValue.GetType(), Properties.Settings.Default.Providers["LocalFileSettingsProvider"], false, null, SettingsSerializeAs.String, attributes, true, true);
                Properties.Settings.Default.Properties.Add(property);
            }
        }
        Properties.Settings.Default.Reload();
    }
}

.....and....

  Dictionary<FrameworkElement, DependencyProperty> savedElements = new Dictionary<FrameworkElement, DependencyProperty>();

public Window_Load(object sender, EventArgs e) {
           savedElements.Add(firstNameText, TextBox.TextProperty);
                savedElements.Add(lastNameText, TextBox.TextProperty);

            SettingsManager.LoadSettings(this, savedElements);
}

private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
        {
            SettingsManager.SaveSettings(this, savedElements);
        }

Answer 4

I typically do this sort of thing by defining a custom [Serializable] settings class and simply serializing it to disk. In your case case you could just as easily store it as a string blog in your SQLite database.