WPF - binding to a property of a custom object that is inside another object

Question

I'm working in WPF 4 / C#. I have two custom classes:

public class c1 {
    public string prop1 { get; set; }

    public c1() {
        prop1 = "world";
    }
}

public class c2 {
    public string prop1 { get; set; }
    public c1 obj1 = new c1();

    public c2() {
        prop1 = "hello";
    }
}

From within XAML, I want to bind to properties of these classes. Here is what I have:

<Window.Resources>
    <my:c2 x:Key="c2"/>
</Window.Resources>
<StackPanel>
    <TextBlock DataContext="{DynamicResource c2}" Text="{Binding prop1}"/>
    <TextBlock DataContext="{DynamicResource c2}" Text="{Binding obj1.prop1}"/>
</StackPanel>

(Here the <my:c2 ../> instantiates the c2 class.) The first TextBlock binding works. The second does not. Why can't I bind to a property on the obj1? I only seem to be able to bind to properties of the immediate class. I want to be able to bind to other stuff like an element in an array that belongs to the immediate class or a property of a child class, as shown above. What am I missing? If I wrap the obj1.prop1 in another property of the immediate class using get/set, it works. But I don't want to have to do that, particularly if I start using arrays, I don't want to wrap each element into a separate property!

Answer 1

Your obj1 is a field, not a property, therefore you can't access the C1 object.

Consider this instead:

public class c2 {
    public string prop1 { get; set; }
    private readonly c1 _obj1;

    public c2() {
        prop1 = "hello";
        _obj1 = new c1();
    }

    public c1 PropObj1 { get { return _obj1; } }
}

And

<TextBlock DataContext="{DynamicResource c2}" Text="{Binding PropObj1.prop1}"/>

PS. Next time better to use an example with standard naming conventions (e.g. lower case fields/variables, upper case properties etc) to allow people to see the problem sooner!

Answer 2

You can't bind to fields, they have to be properties.