title: Why is the Binding Format event called twice?
body: <p>I am playing around with data binding and noticed that the Binding Format is called twice upon loading the form in the code below.  I thought it would only happen once when the test class TextBoxText property is fist bound to textbox1.  Is this normal?  If not, then what can I do to prevent it? Note, when I press button1 and it changes the TextBoxText property of the test class, the format event fires once as expected.</p>
  
  <pre><code>public partial class Form1 : Form
  {
      Test _test = new Test();
      public Form1()
      {
          InitializeComponent();
          Binding binding = new Binding("Text", _test, "TextBoxText");
          binding.Format += new ConvertEventHandler(Binding_Format);
          this.textBox1.DataBindings.Add(binding);
      }
  
      private void Binding_Format(object sender, ConvertEventArgs e)
      {            
          Debug.WriteLine("Format");
      }
  
      private void button1_Click(object sender, EventArgs e)
      {
          _test.TextBoxText = "test1";
      }
  }
  
  
  
  class Test : INotifyPropertyChanged
  {
      private string _text;
  
      public string TextBoxText 
      {
          get { return _text; }
          set 
          { 
              _text = value;
              OnPropertyChanged(new PropertyChangedEventArgs("TextBoxText"));
          } 
      }
  
      private void OnPropertyChanged(PropertyChangedEventArgs e)
      {
          PropertyChanged(this, e);
      }
  
      #region INotifyPropertyChanged Members
  
      public event PropertyChangedEventHandler PropertyChanged;
  
      #endregion
  </code></pre>