Question

I am trying to understand Binding so I have come up with a very simple program to try and test it.

I have the following element in my MainWindow:

<ComboBox Name="comboBox1" ItemsSource="{Binding}" />

In my Code I have the following observable collection:

public ObservableCollection<string> ComboItems = new ObservableCollection<string>();

I can successfully add items this way at any point during runtime:

comboBox1.DataContext = ComboItems;
ComboItems.Clea();
ComboItems.Add("Item");

My question is, how could I set the DataContext in XAML so that I don’t have to do it in code? Is it possible?

Thank you!

Answer 1

Something common is:

<Window DataContext="{Binding RelativeSource={RelativeSource Self}}">
    <ComboBox ItemsSource="{Binding ComboItems}" .../>

However usually you want to inject another object instance as DataContext, have a look at the MVVM pattern for example. Properties in WPF are inherited, so the ComboBox has the DataContext of the Window, it can be overwritten at any level though.

Note: For the Binding to work ComboItems needs to be a public property, not a field.

Resources of interest:

• Data Binding Overview
• Data Templating Overview
• Depedency Properties Overview