Xamarin.forms how to auto save user name like browser - xamarin

Question

I am developing a mobile application using Xamarin.Forms
I had the following Home page contains login info:
How can we have the application to automatically save the user name, so that they do not have to type it in each time (as in a browser)?

Answer 1

You can use Properties dictionary in Xamarin.Forms Application class. And let the Xamarin.Forms framework handle persisting user name between app restarts and pausing/resuming your app.
Save user name by writing it to Properties dictionary
var properties = Xamarin.Forms.App.Current.Properties;
if(!properties.ContainsKey("username")
{
properties.Add("username", username);
}
else
{
properties["username"] = username;
}
Then, when your login screen is about to appear (for example in OnAppearing method) check Properties for user name:
var properties = Xamarin.Forms.App.Current.Properties;
if(properties.ContainsKey("username")
{
var savedUsername = (string)properties["username"];
}
If it's not there, then it means that this is first time when user log in into your application.

Answer 2

A very similar question was posed just a few days ago - my answer on that question also applies to your question: The best way to save Configuration data in Xamarin.Forms based app?
Essentially, you want to store the information using the native settings functionality. I would advise against using Application.Properties for now. It is currently not reliable on Android, and in the past has had other problems. The nuget package referenced in my linked answer is a better approach and will save you some headache in the future.

Answer 3

The right way to be done is through the App settings plugin
https://github.com/jamesmontemagno/Xamarin.Plugins/tree/master/Settings
What i did in my application is.
1) Installed Plugin.Settings from nuget
2)Added to Helpers->Settings.cs (autogenerated file by plugin) the following
public static class Settings
{
private static ISettings AppSettings
{
get { return CrossSettings.Current; }
}
private const string UserNameKey = "username_key";
private static readonly string UserNameDefault = "demo";
public static string UserName
{
get { return AppSettings.GetValueOrDefault<string>(UserNameKey, UserNameDefault); }
set { AppSettings.AddOrUpdateValue<string>(UserNameKey, value); }
}
}
3)In order to keep the username in the Application Context set
Settings.UserName = ViewModel.Username;
4)When you login screen starts
string username = Settings.UserName;

Answer 4

The answer is simple: persistance. Servers do this by setting cookies containing the data (or reference to it) that they want you to see when rendering the form field.
In order to do this in an app (with Xamarin for instance), you need to store the user's data into a file or database somewhere. Since you're using Xamarin you can probably use some sort of ConfigurationManager to keep track of this.
Obviously you could just create a config file in the local storage you have for your app (I don't think you need permissions to create files in that space).
When you have the info stored somewhere, just retrieve it and set the input's value to it.