title: How to create an event on property changing and changed event in C#
body: <p>I created a property</p>
  
  <pre><code>public int PK_ButtonNo 
  {
      get { return PK_ButtonNo; }
      set { PK_ButtonNo = value; }
  }
  </code></pre>
  
  <p>Now I want to add events to this property for value changing and changed.</p>
  
  <p>I wrote two events. Here I want both the events to contain changing value as well as changed value.</p>
  
  <p>i.e </p>
  
  <p>When user implements the event. He must have <code>e.OldValue</code>, <code>e.NewValue</code> </p>
  
  <pre><code>public event EventHandler ButtonNumberChanging;
  public event EventHandler ButtonNumberChanged;
  
  public int PK_ButtonNo 
  {
      get { return PK_ButtonNo; }
      private set
      {
          if (PK_ButtonNo == value)
              return;
  
          if (ButtonNumberChanging != null)
              this.ButtonNumberChanging(this,null);
  
          PK_ButtonNo = value;
  
          if (ButtonNumberChanged != null)
              this.ButtonNumberChanged(this,null);
      }
  }
  </code></pre>
  
  <p>How will I get the changing value and changed value when I implement this event.</p>