interface IContainer : IDisposable {
  ComponentCollection Components { get; }
  void Add(IComponent component);
  void Add(IComponent component, string 
      name);
  void Remove(IComponent component);
}

interface ISite : IServiceProvider {
  IComponent Component { get; }
  IContainer Container { get; }
  bool DesignMode { get; }
  string Name { get; set; }
}

interface IComponent : IDisposable {
  ISite Site { get; set; }
  event EventHandler Disposed;
}

class Component : MarshalByRefObject, IComponent, IDisposable {
  public IContainer Container { get; }
  public ISite Site { virtual get; virtual set; }
}

IDesignerHost designerHost = this.Container as  
    IDesignerHost;

class ClockControl : Control {
  public ClockControl() { ... }
  public DateTime Alarm { get { ... } set { ... } }
  public event onSoundTheAlarm SoundTheAlarm;
  •••
}

class ClockComponent : Component {
  public ClockComponent(IContainer container) {
    // Add object to container's list so that
    // we get notified when the container goes away
    container.Add(this);
  }
  •••
}

class ClockComponentHostForm : Form {
  ClockComponent clockComponent1;
  IContainer components;
  •••
  void InitializeComponent() {
    this.components = new System.ComponentModel.Container();
    this.clockComponent1 = new ClockComponent(this.components);
    •••
  }
  •••
}

class ClockComponentHostForm : Form {
  •••
  protected override void Dispose( bool disposing ) {
    if( disposing ) {
      if (components != null) {
        // Call each component's Dispose method
        components.Dispose();
      }
    }
    base.Dispose( disposing );
  }
}

class ClockComponent : Component {
  •••
  protected override void Dispose(bool disposing) {
    // Dispose of resources
    •••

    // Let base class have a chance
    base.Dispose(disposing);
  }
}

   void timer_Tick(object sender, EventArgs e) {
     this.Refresh();
     •••
   }

void timer_Tick(object sender, EventArgs e) {
  if( this.DesignMode ) return;
  this.Refresh();
  •••
}

[ ToolboxBitmapAttribute(typeof(ClockControl), 
  "images.ClockControl.ico") ]
class ClockControl : Control { ... }

[ BrowsableAttribute(false) ]
public bool IsItTimeForABreak {
  get { ... }
  set { ... }
}

[
  CategoryAttribute("Behavior"),
  DescriptionAttribute("Alarm for late risers")
]
public DateTime Alarm {
  get { ... }
  set { ... }
}

[
  CategoryAttribute("Appearance"),
  DescriptionAttribute("Determines whether digital time is shown"),
  DefaultValueAttribute(true)
]
public bool ShowDigitalTime {
  get { ... }
  set { ... }
}

[ DefaultEventAttribute("SoundTheAlarm") ]
class ClockControl : Control { ... }

[ DefaultPropertyAttribute("ShowDigitalTime") ]
class ClockControl : Control { ... }

[
  CategoryAttribute("Appearance"),
  DescriptionAttribute("Determines whether digital time is shown"),
  DefaultValueAttribute(true),
  DesignerSerializationVisibilityAttribute
  (DesignerSerializationVisibility.Hidden)
]
public bool ShowDigitalTime {
  get { ... }
  set { ... }
}

DateTime _primaryAlarm = DateTime.Now;
DateTime _backupAlarm = DateTime.Now.AddMinutes(10);

public interface ISupportInitialize {
  public void BeginInit();
  public void EndInit(); 
}

class ClockControl : ..., ISupportInitialize {
  void ISupportInitialize.BeginInit() {}
  void ISupportInitialize.EndInit() {
    // Check alarm values
    if( _primaryAlarm >= _backupAlarm )
      throw new Exception("Primary alarm must be before backup alarm");
  }
  •••
}

class ClockControl : ..., ISupportInitialize {
  void ISupportInitialize.BeginInit() {}
  void ISupportInitialize.EndInit() {
    if( !this.DesignMode ) {
      •••
      //Initialize timer
      _timer.Interval = 1000;
      _timer.Tick += new System.EventHandler(this.timer_Tick);
      _timer.Enabled = true;
    }
  }
  •••
}

[ ProvidePropertyAttribute("TimeZoneModifier", typeof(PictureBox)) ]
public class ClockControl : System.Windows.Forms.Control { ... }

class ClockControl : ..., IExtenderProvider {
  bool IExtenderProvider.CanExtend(object extendee) {
    // Don't extend self
    if( extendee == this ) return false;
    
    // Extend suitable controls
    return( (extendee is PictureBox) ||
            (extendee is Panel) );
  }
  •••
}

public class ClockControl : System.Windows.Forms.Control, 
IExtenderProvider {
  private HashTable _timeZoneModifiers = new HashTable();

     public string GetTimeZoneModifier(Control extendee) {
       return Convert.ToString(_timeZoneModifiers[extendee]);
     }
     •••
   }

class ClockControl : ..., IExtenderProvider {
  [
    Category("Behavior"),
    Description("Sets the timezone difference from the current time"),
    DefaultValue("")
  ]
  public string GetTimeZoneModifier(Control extendee) { ... }
  •••
}

<ExtendedPropertyName> on <ExtenderProviderName>

void InitializeComponent() {
  •••
  // pictureBox1
  this.pictureBox1.Location = new System.Drawing.Point(62, 163);
  this.pictureBox1.Name = "pictureBox1";
  this.pictureBox1.TabIndex = 5;
  this.pictureBox1.TabStop = false;
  this.clockControl1.SetTimeZoneModifier(this.pictureBox1, "-2");
  •••
}