Merge Multi Colums in Binding

2 Comments

• Just goes to show the importance of comments - not to mention an explanation. This code wouldn't pass code review.
  

• Try this instead
  
  ///
  /// Initializes a new instance of the MultipleBinding class.
  ///
  /// The name of the control property to bind.
  
  /// An Object that represents the data source.
  
  /// The property or list to bind to.
  
  /// A format string to use. Each dataMember must be encased in {}. Standard String format specifiers may be used. e.g. {Weight:D5}
  
  public MultipleBinding(string propertyName, object dataSource, string dataMember, string bindingString)
  : base(propertyName, dataSource, dataMember)
  {
  _bindingString = bindingString;
  
  // All other dataMembers besides the main one must be subscribed to the changed event to pick up changes
  String[] props = FormatProperties();
  foreach (string prop in props)
  {
  if (prop != dataMember)
  {
  EventDescriptorCollection events = TypeDescriptor.GetEvents(dataSource);
  EventDescriptor e = events.Find(prop + "Changed", true);
  if (e != null)
  e.AddEventHandler(dataSource, new EventHandler(PropertyChanged));
  }
  }
  }
  
  private void PropertyChanged (object sender, EventArgs e)
  {
  ReadValue();
  }
  
  // Returns a list of properties that are referenced in the format string
  private string[] FormatProperties()
  {
  System.Collections.Generic.List temp = new List();
  
  string s = _bindingString;
  int i = 0;
  while (i >= 0)
  {
  i = s.IndexOf("{", i);
  if (i >= 0)
  {
  string prop = s.Substring(i + 1).Split('}')[0];
  int j = prop.IndexOf(":");
  if (j > 0) prop = prop.Substring(0, j);
  temp.Add(prop);
  i++;
  }
  }
  
  return temp.ToArray();
  }
  
  // Returns a list of format modifiers that are used in the format string
  private string[] FormatModifiers()
  {
  System.Collections.Generic.List temp = new List();
  
  string s = _bindingString;
  int i = 0;
  while (i >= 0)
  {
  i = s.IndexOf("{", i);
  if (i >= 0)
  {
  string prop = s.Substring(i + 1).Split('}')[0];
  int j = prop.IndexOf(":");
  if (j > 0)
  prop = prop.Substring(j);
  else
  prop = "";
  temp.Add(prop);
  i++;
  }
  }
  
  return temp.ToArray();
  }
  
  ///
  /// Generates the bound text based on the format string.
  ///
  /// A ConvertEventArgs that contains the event data.
  
  protected override void OnFormat( ConvertEventArgs e )
  {
  // The bound object
  Object cur = this.BindableComponent.BindingContext[this.DataSource].Current;
  // A list of all its properties
  PropertyDescriptorCollection pdc = TypeDescriptor.GetProperties(cur);
  
  // The string we are building
  string s = _bindingString;
  
  string[] props = FormatProperties();
  string[] formats = FormatModifiers();
  
  for (int i = 0; i 0)
  {
  val = string.Format("{0" + formats[i] + "}", pdc[props[i]].GetValue(cur));
  s = s.Replace("{" + props[i] + formats[i] + "}", val);
  }
  else
  {
  // Just get the property
  val = pdc[props[i]].GetValue(cur).ToString();
  s = s.Replace("{" + props[i] + "}", val);
  }
  
  }
  e.Value = s;
  }
  }