I want to save user data on client's machine for c# app

Question

For my c# windows form application, I want to preserve some user data on the client machine. What should be my steps (eg. local database, xml files), which one would be most secured.

Answer 1

The built in way to handle this is the settings class.

In the project file there is even a 'settings' tab you can enter values for your app. Access them at run time like

        Width = Settings1.Default.Width;
        Height = Settings1.Default.Height;
        Top = Settings1.Default.Top;
        Left = Settings1.Default.Left;

Save() and Load() are also available.

Answer 2

The code I use for all my programs to load and save settings at startup and shutdown:

private void Window_Closing(object sender, CancelEventArgs e)
{
    SaveAppSettings();

}
private void LoadAppSettings()
{
    if (Properties.Settings.Default.LastWindowSize.Width > System.Windows.SystemParameters.WorkArea.Width)
        this.Width = System.Windows.SystemParameters.WorkArea.Width - 1; // stay within screen resolution
    else
        this.Width = Properties.Settings.Default.LastWindowSize.Width;
    if (Properties.Settings.Default.LastWindowSize.Height > System.Windows.SystemParameters.WorkArea.Height)
        this.Height = System.Windows.SystemParameters.WorkArea.Height - 1; // stay within screen resolution
    else
        this.Height = Properties.Settings.Default.LastWindowSize.Height;
    if (Properties.Settings.Default.LastWindowPos.X > 0) // keep it sane, otherwise window appears to disappear
        this.Left = Properties.Settings.Default.LastWindowPos.X;
    if(Properties.Settings.Default.LastWindowPos.Y > 0)
        this.Top = Properties.Settings.Default.LastWindowPos.Y;
}
private void SaveAppSettings()
{
    if (this.WindowState == WindowState.Normal)
    {
        Properties.Settings.Default.LastWindowPos = new System.Drawing.Point((int)this.Left, (int)this.Top);
        Properties.Settings.Default.LastWindowSize = new System.Drawing.Size((int)this.Width, (int)this.Height);
    }
    else
    {
        Properties.Settings.Default.LastWindowPos
           = new System.Drawing.Point((int)this.RestoreBounds.Left, (int)this.RestoreBounds.Top);
        Properties.Settings.Default.LastWindowSize
           = new System.Drawing.Size((int)this.RestoreBounds.Width, (int)this.RestoreBounds.Height);
    }
    Properties.Settings.Default.Save();
}

I put in some checks for rational sizing since I use VMWare Fusion. If the fusion window is smaller than the last application size you could get into a situation where you can no longer resize the application properly. This should give you an idea of one way to do things.

Answer 3

I would use App.config and access the settings using the ConfigurationManager.AppSettings class.

App.Config

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
    </startup>
  <appSettings>
    <add key="Setting1" value="true"/>
    <add key="Setting2" value="value"/>
  </appSettings>
</configuration>

Access settings from your application with the following

bool setting1 = Convert.ToBolean(ConfigurationManager.AppSettings["Setting1"]);
string setting2 = ConfigurationManager.AppSettings["Setting2"];

To update settings create a static helper method

public static void UpdateAppSetting(string key, string value)
{
    var configuration = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
    configuration.AppSettings.Settings[key].Value = value;
    configuration.Save();

    ConfigurationManager.RefreshSection("appSettings");
}

See the link below for more examples.

https://msdn.microsoft.com/en-us/library/system.configuration.configurationmanager.appsettings(v=vs.110).aspx