PropertyChanged not affected on collection changes

Question

I use the following dictionary:

private Dictionary<string, string> _myDic;
public Dictionary<string, string> MyDic
{
   get
   {
       return _myDic;
   }
   set
   {
      if (_myDic!= value)
      {
         _myDic= value;
         NotifyPropertyChanged("MyDic");
      }
    }
}

Is bind to a combobox in my view.

Everything works.

The problem is that when I add item is not updated if already opened the combobox.

Only if it remains closed from the beginning then the change appears on the screen.

I have a single place where I add item to dictionary and immediately I used the event propertychanged hoping it will affect the UI:

MyDic.Add(strK, strV);
NotifyPropertyChanged("MyDic");

But it did not help (although the event did not coming null).

I understand that it is because it is a change in the collection, not the object itself. My problem is that I can not change the type of this variable to cutsom ObservableDictionary for various reasons.

My question is why the NotifyPropertyChanged("MyDic"); is not affected. And is there any other way (except to change the type) to deal with this problem?

Have you tried to do the same with the Count property of the dictionary? — Programmer, Oct 13 '13 at 10:09
@user2760623. What does this mean to do the same with the Count property of the dictionary? You can expand? — Hodaya Shalom, Oct 13 '13 at 10:11
@JonSkeet. I mean the list in the UI not changed if already opened the combobox. — Hodaya Shalom, Oct 13 '13 at 10:33

score 0 · Accepted Answer · answered Oct 13 '13 at 10:52

I found a way a bit primitive. And yet it worked.

I created another dictionary which I added the item to it.

Then I changed my dictionary to the local dictionary:

Dictionary<string, string> _dic = new Dictionary<string, string>();
foreach (var str in MyDic)
   _dic.Add(str.Key, str.Value);
 _dic.Add(strK, strV);
  MyDic= _dic;

If someone has a better way I'd love to hear.

PropertyChanged not affected on collection changes

1 Answers1