using System;
using System.IO;

namespace NHibernate.Helper.DbSpecific
{
    public class SqlCEDbHelper
    {
        const string engineTypeName = "System.Data.SqlServerCe.SqlCeEngine, System.Data.SqlServerCe";

        /// <summary>
        /// note: this method will delete existing db and then creates a new one.
        /// </summary>
        /// <param name="filename"></param>
        /// <param name="password"></param>
        public static void CreateEmptyDatabaseFile(string filename, string password = "")
        {
            if (File.Exists(filename))
                File.Delete(filename);

            var type = System.Type.GetType(engineTypeName);
            var localConnectionString = type.GetProperty("LocalConnectionString");
            var createDatabase = type.GetMethod("CreateDatabase");

            var engine = Activator.CreateInstance(type);

            string connectionStr = string.Format("Data Source='{0}';Password={1};Encrypt Database=True", filename, password);
            if (string.IsNullOrWhiteSpace(password))
                connectionStr = string.Format("Data Source='{0}'", filename);

            localConnectionString.SetValue(
                obj: engine,
                value: connectionStr,
                index: null);
            createDatabase.Invoke(engine, new object[0]);
        }

        /// <summary>
        /// use this method to compact or encrypt existing db or decrypt it to a new db with all records
        /// </summary>
        /// <param name="sourceConnection"></param>
        /// <param name="destConnection"></param>
        public static void CompactDatabase(string sourceConnection, string destConnection)
        {
            var type = System.Type.GetType(engineTypeName);
            var engine = Activator.CreateInstance(type);

            var localConnectionString = type.GetProperty("LocalConnectionString");
            localConnectionString.SetValue(
                obj: engine,
                value: sourceConnection,
                index: null);

            var compactDatabase = type.GetMethod("Compact");
            compactDatabase.Invoke(engine, new object[] { destConnection });
        }
    }
}

Data Source=c:\path\db.sdf;Password=1234;Encrypt Database=True

private Configuration getConfig()
{
            var configure = new Configuration();
            configure.SessionFactoryName("BuildIt");

            configure.DataBaseIntegration(db =>
            {
                db.ConnectionProvider<DriverConnectionProvider>();
                db.Dialect<MsSqlCe40Dialect>();
                db.Driver<SqlServerCeDriver>();
                db.KeywordsAutoImport = Hbm2DDLKeyWords.AutoQuote;
                db.IsolationLevel = IsolationLevel.ReadCommitted;
                db.ConnectionString = ConnectionString;
                db.Timeout = 10;

                //for testing ...
                db.LogFormattedSql = true;
                db.LogSqlInConsole = true;
            });

            return configure;
}

install-package WcfRestContrib

[ServiceContract]
public interface IBooksService
{    
    [OperationContract]
    void AddBook(string isbn, Book book);
}

[ServiceContract]
public interface IBooksService
{
    [WebInvoke(UriTemplate = "/{isbn}", Method=Verbs.Put)]
    [WebDispatchFormatter]
    [OperationContract]
    void AddBook(string isbn, Book book);
    ....
}

[WebDispatchFormatterConfiguration("application/xml")]
[WebDispatchFormatterMimeType(typeof(WcfRestContrib.ServiceModel.Dispatcher.Formatters.PoDataContract), "application/xml",  "text/xml")]
[WebDispatchFormatterMimeType( typeof(WcfRestContrib.ServiceModel.Dispatcher.Formatters.DataContractJson),  "application/json")]
[WebDispatchFormatterMimeType( typeof(WcfRestContrib.ServiceModel.Dispatcher.Formatters.FormUrlEncoded), "application/x-www-form-urlencoded")]
public class Books : IBooksService 
{    
   public void AddBook(string isbn, Book book)
   {
   }
}

<system.serviceModel>
    <extensions>
        <behaviorExtensions>
            <add name="webFormatter" 
                 type="WcfRestContrib.ServiceModel.Configuration.WebDispatchFormatter.ConfigurationBehaviorElement, WcfRestContrib, 
                       Version=x.x.x.x, Culture=neutral, PublicKeyToken=89183999a8dc93b5"/>
        </behaviorExtensions>
    </extensions>
    <serviceBehaviors>
        <behavior name="Rest">
          <webFormatter>
            <formatters defaultMimeType="application/xml">
              <formatter mimeTypes="application/xml,text/xml" 
                         type="WcfRestContrib.ServiceModel.Dispatcher.Formatters.PoxDataContract, WcfRestContrib"/>
              <formatter mimeTypes="application/json" 
                         type="WcfRestContrib.ServiceModel.Dispatcher.Formatters.DataContractJson, WcfRestContrib"/>
              <formatter mimeTypes="application/x-www-form-urlencoded" 
                         type="WcfRestContrib.ServiceModel.Dispatcher.Formatters.FormUrlEncoded, WcfRestContrib"/>
            </formatters>
          </webFormatter>
        </behavior>
    </serviceBehaviors>
</system.serviceModel>

[WebDispatchFormatter(WebDispatchFormatter.FormatterDirection.Outgoing)]  

        <Button Command="{Binding IncreaseStepsCountCommand}" Text="Button with command binding" />
        <Button Text="Button with event to command">
            <Button.Behaviors>
                <prismBehaviors:EventToCommandBehavior Command="{Binding IncreaseStepsCountCommand}" EventName="Clicked" />
            </Button.Behaviors>
        </Button>

xmlns:prismBehaviors="clr-namespace:Prism.Behaviors;assembly=Prism.Forms"

        <Label Text="{Binding StepsCount, StringFormat='{}Button tapped {0} times!'}">
            <Label.GestureRecognizers>
                <SwipeGestureRecognizer Command="{Binding IncreaseStepsCountCommand}" Direction="Left" />
            </Label.GestureRecognizers>
        </Label>

<Label Text="{Binding StepsCount, StringFormat='{}Button tapped {0} times!'}" />

        <Entry x:Name="MyEntry" />
        <Label Text="{Binding Text, Source={x:Reference MyEntry}}" />

<ContentPage
...
    xmlns:vm="clr-namespace:XamApp.ViewModels"
    x:DataType="vm:HelloWorldViewModel">

        private int _StepsCount;
        public int StepsCount
        {
            get => _StepsCount;
            set => SetProperty(ref _StepsCount, value);
        }

public int StepsCount { get; set; }