Display Consistent Value of an Item using MVVM and WPF
- by Blake Blackwell
In my list view control (or any other WPF control that will fit the situation), I would like to have one TextBlock that stays consistent for all items while another TextBlock that changes based on the value in the ObservableCollection. Here is how my code is currently laid out:
XAML
<ListView ItemsSource="{Binding Path=MyItems, Mode=TwoWay}">
<ListView.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock x:Name="StrVal" Text="{Binding StrVal}" />
<TextBlock x:Name="ConstVal" Text="{Binding MyVM.ConstVal}" />
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
Model
public class MyItem
{
public string StrVal { get; set; }
}
ViewModel
public class MyVM
{
public MyVM()
{
ObservableCollection<MyItem> myItems = new ObservableCollection<MyItem>();
for (int i = 0 ; i < 10; i++)
myItems.Add(new MyItem { StrVal = i.ToString()});
MyItems = myItems;
ConstVal = "1";
}
public string ConstVal { get; set; }
public ObservableCollection<MyItem> MyItems { get; set; }
}
Code Behind
this.DataContext = new MyVM();
The StrVal property repeats correctly in the ListView, but the ConstVal TextBlock does not show the ConstVal that is contained in the VM. I would guess that this is because the ItemsSource of the ListView is MyItems and I can't reference other variables outside of what is contained in the MyItems.
My question is: How do I get ConstVal to show the value in the ViewModel for all listviewitems that will be controlled by the Observable Collection of MyItems.
