<?xml version="1.0" encoding="utf-8" ?>
<configuration>
 <configSections>
   <section name="log4net"
            type="log4net.Config.Log4NetConfigurationSectionHandler,log4net" />
 </configSections>

 <connectionStrings>
   <!--NHSessionManager-->
   <add name="DbConnectionString"
        connectionString="Data Source=(local);Initial Catalog=HelloNHibernate;Integrated Security = true"/>
 </connectionStrings>

 <log4net>
   <appender name="rollingFile"
             type="log4net.Appender.RollingFileAppender,log4net" >
     <param name="File" value="NHibernate_Log.txt" />
     <param name="AppendToFile" value="true" />
     <param name="DatePattern" value="yyyy.MM.dd" />
     <rollingStyle value="Size" />
     <maxSizeRollBackups value="10" />
     <maximumFileSize value="500KB" />
     <staticLogFileName value="true" />
     <layout type="log4net.Layout.PatternLayout,log4net">
       <conversionPattern value="%d %p %m%n" />
     </layout>
   </appender>
   <logger name="NHibernate.SQL">
     <level value="ALL" />
     <appender-ref ref="rollingFile" />
   </logger>
 </log4net>

</configuration>

log4net.Config.XmlConfigurator.Configure();           

// Configure log4net using the .config file
[assembly: log4net.Config.XmlConfigurator(Watch = true)]

2009-10-18 20:03:54,187 DEBUG INSERT INTO [Student] (Name) VALUES (@p0); select SCOPE_IDENTITY();@p0 = 'Vahid'

log4net.LogManager.GetLogger("NHibernate.SQL").Info("test1");

private void btnProcessWithDoEvents_Click(object sender, EventArgs e)
{
for (int i = 0; i < 100000; i++)
{
  TextBox1.Text = "Processing " + i.ToString();
  Application.DoEvents();
}
}

private void btnStartTimer_Click(object sender, EventArgs e)
{
  this.timer1.Enabled = true;
  this.timer1.Start();
  this.timer1.Interval = 20;

}

private void timer1_Tick(object sender, EventArgs e)
{
  Thread.Sleep(50);
  Application.DoEvents();
}

class Visitor {
    visit(item){}
}

class BookVisitor extends Visitor {
    visit(book) {
        var cost=0; 
        if(book.getPrice() > 50) 
        { 
            cost = book.getPrice()*0.50 
        } 
        else{
            cost = book.getPrice()
        }     
        console.log("Book name: "+ book.getName() + "\n" + "ID: " + book.getID() + "\n" + "cost: "+ cost); 
        return cost; 
    }
}

class Book{
    constructor(id,name,price){
        this.id = id
        this.name = name
        this.price = price
    }
    getPrice(){
        return this.price
    }
    getName(){
        return this.name
    }
    getID(){
        return this.id
    }
    accept(visitor){
        return visitor.visit(this)
    }
}

var visitor = new BookVisitor()
var book1 = new Book("#1234","lordOftheRings",80)
book1.accept(visitor)

class Book{
    constructor(id,name,price){
        this.id = id
        this.name = name
        this.price = price
    }
    //code...
}

getPrice(){
    return this.price
}

getName(){
    return this.name
}

getID(){
    return this.id
}

accept(visitor){
    return visitor.visit(this)
}

1. زمانیکه نیاز است عملیاتی مشابه، بر روی شیء‌های متفاوتی از یک data structure  انجام شود. 
   
2. زمانیکه نیاز است عملیاتی خاص، بر روی شیء‌های متفاوتی از data structure انجام شود. 
   
3. زمانیکه می‌خواهید توسعه پذیری را برای کتابخانه‌ها (libraries) یا فریم ورک‌ها (frameworks) اضافه کنید.
   

 var tags = _blogRepository.GetAllTags(blogID).OrderBy(s => s.Id);
    var currenttags = _mapper.Map<IList<TagsViewModel>>(tags);
            if (currenttags == null)
            {
                return NotFound();

            }
            return Json(currenttags.AsQueryable()
                       .ToDataSourceResult(request.Take, request.Skip, request.Sort,
                                                       request.Filter));

sealed class DeviceStatus : IEquatable<DeviceStatus>
    {
        [Flags]
        private enum StatusRepresentation
        {
            AllFine = 0,
            NotOperational = 1,
            VisiblyDamaged = 2,
            CircuitryFailed = 4
        }

        private StatusRepresentation Representation { get; }

        private DeviceStatus(StatusRepresentation representation)
        {
            this.Representation = representation;
        }

        public static DeviceStatus AllFine() =>
            new DeviceStatus(StatusRepresentation.AllFine);

        public DeviceStatus WithVisibleDamage() =>
            new DeviceStatus(this.Representation | StatusRepresentation.VisiblyDamaged);

        public DeviceStatus NotOperational() =>
            new DeviceStatus(this.Representation | StatusRepresentation.NotOperational);

        public DeviceStatus Repaired() =>
            new DeviceStatus(this.Representation & ~StatusRepresentation.NotOperational);

        public DeviceStatus CircuitryFailed() =>
            new DeviceStatus(this.Representation | StatusRepresentation.CircuitryFailed);

        public DeviceStatus CircuitryReplaced() =>
            new DeviceStatus(this.Representation & ~StatusRepresentation.CircuitryFailed);

        public override int GetHashCode() => (int)this.Representation;

        public override bool Equals(object obj) => this.Equals(obj as DeviceStatus);

        public bool Equals(DeviceStatus other) =>
            other != null && this.Representation == other.Representation;

        public static bool operator ==(DeviceStatus a, DeviceStatus b) =>
            (object.ReferenceEquals(a, null) && object.ReferenceEquals(b, null)) ||
            (!object.ReferenceEquals(a, null) && a.Equals(b));

        public static bool operator !=(DeviceStatus a, DeviceStatus b) => !(a == b);
    }

=?UTF-8?B?QW5hbHl0aWNzIHZhaGlkbmFzaXJpLmJsb2dzcG90LmNvbSAyMDA4MTIyNiAo2KLZhdin?= =?UTF-8?B?2LEg2LPYp9mK2Kop?=

=?charset?encoding?EncodedText?=

//using System.Text;
public static string Base64ToString(string charset, string encodedString)
{
  //تبدیل بیس 64 به آرایه‌ای از بایت‌ها
  byte[] buffer = Convert.FromBase64String(encodedString);
  //تبدیل آرایه‌ای از بایت‌ها به رشته با توجه به انکدینگ مربوطه
  return Encoding.GetEncoding(charset).GetString(buffer);
}

string subject = Base64ToString("utf-8", "QW5hbHl0aWNzIHZhaGlkbmFzaXJpLmJsb2dzcG90LmNvbSAyMDA4MTIyNiAo2KLZhdin2LEg2LPYp9mK2Kop");