WPF: What is the difference between the Content and DataContext properties?

Question

As I understand it...

• DataContext property
  • "controls use this property as a data source"
  • "is a property that each framework element has that can be used to flow data into the screen"
  • "DataContext has scope"
  • "the scope is established according to where the DataContext is assigned to in the object tree"
  • "if you set the DataContext on a parent element (e.g. a Window), that property will flow down to all child elements (e.g. a text box)"
• Content property
  • This property takes on many names depending on the control that is being used:
    • ContentControl.Content
    • ItemsControl.ItemsSource
    • Items.ItemsSource
    • HeaderedContentControl.Header
    • HeaderedContentControl.Content

So my question is: what is the difference between the Content and DataContext properties? There is a nuance here that I am missing. Is it...

1. While the DataContext flows data into the UI,
2. It is the job of the Content property to determine (usually threw a binding) what will be displayed (via ContentPresenter + ContentTemplate)

SAMPLE CODE

<Window x:Name="myWindow" DataContext="{Binding ClassA}> 
    <StackPanel> <!-- DataContext is set to ClassA -->

        <!-- DataContext is set to ClassA, ClassA.Name will be displayed -->
        <Label Content="{Binding Name}" />
    </StackPanel>
 </Window>

REFERENCES

• MSDN: ContentControl.Content Property
• MSDN: FrameworkElement.DataContext Property
• MSDN: WPF Content Model
  • worth reading
• StackOverflow: What is DataContext for?

Answer 1

DataContext is a more general feature in WPF, as suggested by its ownership by the low-level FrameworkElement class.

• it participates in bindings for all framework elements, as the default binding source.
• as you mentioned, an element's DataContext is passed down to child elements.

Content is much more specific:

• it is a dependency property specific to a very limited set of controls (mostly those controls that inherit from ContentControl -- other controls such as ListBox do not own a Content property themselves, but use a ContentControl somewhere in their control templates).
• it is not passed down like the DataContext, but is rather concerned solely with the owning Control and its immediate relationships (ie, bindings)
• it is used by controls that call for something to be displayed, where the control itself does not know or care what type of object that will be.
• it is often used in cojunction with ContentTemplate -- that is, Content is what to display, and ContentTemplate is how to display it. (Button is a good example of this.)