Question

• I have Window that has a ListBox
• ListBox(MyListBox) has a DataTable for its DataContext
• ListBox’s ItemSource is : {Binding}
• Listbox has a UserControl(MyUserControl) as DataTemplate
• UserControl has RadioButtons and TextBoxes (At first They’re filled with values from DataTable and then user can change them)
• Window has one Submit Button

What I want to do is, when user clicks the submit button

• For each ListBox Item, get the values form UserControl’s TextBoxes and RadioButtons.

I was using that method for this job :

foreach(var element in MyListBox.Items)
{ 
  var border = MyListBox.ItemContainerGenerator.ContainerFromItem(element)as FrameworkElement;
  MyUserControl currentControl = VisualTreeHelper.GetChild(VisualTreeHelper.GetChild(VisualTreeHelper.GetChild(myBorder,0) as Border,0)as ContentPresenter,0)as MyUserControl;
  //And use currentControl
}

I realised nothing when using 3-5 items in Listbox. But when I used much more items, I saw that “var border” gets “null” after some elements looped in foreach function.

I found the reason here :
ListView.ItemContainerGenerator.ContainerFromItem(item) return null after 20 items

So what can I do now? I want to access all items and get their values sitting on user controls.

Thanks

Answer 1

You should use objects who implement INotifyPropertyChanged and bind an ObservableCollection of it to the ItemSource
And then you can get all the list of items.

Here some quick links from MSDN to get more informations
How to: Implement Property Change Notification
Binding Sources Overview

You should google for some tutorials about this.