Events in Canvas works only for last element - wpf

Question

I use ListView to display list of Buttons. While using StackPanel or WrapPanel as ItemsPanel of the ListView, everything works fine. When I try Canvas only the last one button from a collection is working, others doesn't even change their background when mouse is over them. Can I make all them work normally?
<ListView ItemsSource="{Binding collection1}">
<ListView.ItemsPanel>
<ItemsPanelTemplate>
<Canvas/>
</ItemsPanelTemplate>
</ListView.ItemsPanel>
<ListView.ItemTemplate>
<DataTemplate>
<Button Margin="{Binding margin}" Width="40" Height="40" Click=button_click />
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
code behind:
public class object1
{
public double x0 { get; set; }
public double y0 { get; set; }
public Thickness margin { get { return new Thickness(x0, y0, 0, 0); } }
public object1(double x, double y)
{
x0= x;
y0 = y;
}
}
public MainWindow : Window
{
public ObservableCollection<object1> collection1 {get;set;}
public MainWindow()
{
InitializeComponent();
DataContext = this;
collection1=new ObservableCollection<object1>();
collection1.Add(new object1(20,20));
collection1.Add(new object1(20,80));
collection1.Add(new object1(80,20));
collection1.Add(new object1(80,80)); // ONLY THAT ONE WORKS
}
}

Answer 1

The problem is the way in which you do the positioning of the Buttons with a Margin inside the ListViewItem. All the ListViewItems lie on top of each other in the Canvas, and only the topmost gets input events.
Move the Margin binding out of the ItemTemplate into an ItemContainerStyle, so that it sets the Margin of a ListViewItem instead of a Button:
<ListView>
<ListView.ItemsPanel>
<ItemsPanelTemplate>
<Canvas/>
</ItemsPanelTemplate>
</ListView.ItemsPanel>
<ListView.ItemContainerStyle>
<Style TargetType="ListViewItem">
<Setter Property="Margin" Value="{Binding margin}"/>
</Style>
</ListView.ItemContainerStyle>
<ListView.ItemTemplate>
<DataTemplate>
<Button Width="40" Height="40" .../>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
When using a Canvas as ItemsPanel I'd strongly suggest to use the Canvas.Left and Canvas.Top properties for positioning item containers. You would usually bind them to properties of the data item type, like your x0 and y0:
<ListView.ItemContainerStyle>
<Style TargetType="ListViewItem">
<Setter Property="Canvas.Left" Value="{Binding x0}"/>
<Setter Property="Canvas.Top" Value="{Binding y0}"/>
</Style>
</ListView.ItemContainerStyle>