WPF Show data from multiple DataContexts in ToolTip of ItemsControl

Question

I am trying to display a tooltip for an item generated by an ItemsControl that needs to pull data from conceptually unrelated sources. For example, say I have a

Answer 1

I had a very similar problem and arrived at this question seeking answers. In the end I came up with a different solution that worked in my case and may be useful to others.

In my solution, I added a property to the child item that references the parent model, and populated it when the children were generated. In the XAML for the ToolTip, I then simply referenced the property from the parent model on each element and set the DataContext to the parent model property.

I felt more comfortable with this solution than creating proxy elements in XAML and referencing them.

Using the example code for this question, you would do the following. Note I have not tested this scenario in a compiler, but have done so successfully implemented this solution in the code for my own scenario.

Item:

public class Item
{
    public List Parent { get; set; }
    public string ItemDescription { get; set; }
    public string ItemName { get; set; }
}

Window:

public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();

            List itemList = new List();
            itemList.Add(new Item() { Parent = this, ItemName = "First Item", ItemDescription = "This is the first item." });
            itemList.Add(new Item() { Parent = this, ItemName = "Second Item", ItemDescription = "This is the second item." });


            this.Items = itemList;
            this.GlobalText = "Something else for the tooltip.";
            this.DataContext = this;
        }

        public string GlobalText { get; private set; }

        public List Items { get; private set; }
    }

XAML: