在ItemsControl的DataTemplate中绑定DataGrid

I have a strange issue occurring with the binding I'm trying to set up. I have an ItemsControl which I'm using to render a WrapPanel which contains a DataGrid for its DataTemplate. Ultimately I want to use the WrapPanel to show one DataGrid for each item in the list that gets bound to the ItemsControl. Right now it creates the correct number of DataGrids and headers, but there is no data actually being bound. I'm not experienced enough with WPF to know where I'm going astray here. The items themselves are Tuple objects. Why aren't my data values getting bound?I have a strange issue occurring with the bindi