ObservableCollection, Databinding

[Nate Bross]

I have a timer that updates an observablecollection<ClassA> every user defined interval (30 seconds for example).

 

I have a Listbox databound to this collection, and pulling updates automatically works fine.

 

I have a textbox and a button, user selects a different item in list (currently using SelectedIndexChanged), I update the textbox.

 

Can I databind the textbox to a property of the currently selected item in my listbox?

[Nate Bross]

I was able to resolve the issue above (I'll post a simplified solution soon). My next, related question is this.

 

How can I force the DataContext to refresh? This is what I'm doing (please stop me if there is a better way)

 

ClassA obj = ((ClassA)listBox1.SelectedItem);
obj.Description = "New description";
DataAccessLayer.UpdateClassA(obj);

 

When I fire this code, my database is updated as expected, but the values in my ListBox are NOT updated until I manually refresh.

 

I thought that C# was "byref" by default, so updating as I've done above should cause the ListBox items to refresh, no?

 

Please help!

[Nate Bross]

Just as additional information, the method to update the database is async, so it returns immediatly; I've also set the datacondext = null; and then back to my ObservableCollection and it is not reflecting my update.

 

Any thoughts?

[Nate Bross]

So, I've found several people with the same issue; and nobody seems to have a good solution.

 

http://www.lhotka.net/weblog/CommentView,guid,06f305de-ec32-4e20-b042-171b58f305ae.aspx

[Nate Bross]

I have not exhausted my testing to verify; but I believe I have found a solution. If I set the DataContext = new List<T>(0); and then to my modified datasource this causes the desired behavior; why DataContext = null; does not work is beyond me.

 

A bit more testing and I'll have confirmed that this is the "solution".

[Nate Bross]

Turns out that I was fooled by the inconsistency of my problem; however, it still seems that it is ALWAYS one "update" behind. Any thoughts would really be helpful. Thanks.