Field Selection in WPF Designer - No Dropdown?

In WPF properties like DisplayMemberPath and ValueMemberPath aren't just properties - an example might be:

<ComboBox    DisplayMemberPath="Addresses[0].Line1"    ValueMemberPath="Address[0].Id"    SelectedValue="{Binding Path=FavoriteAddressId}"    ...    />

If the designer properties only let you select from a list of properties, you'd be missing out on some pretty useful features. But you are right that providing a list in addition to being able to type it in would be useful.

There's always been a power struggle between WPF's binding system, which is quite dynamic, and the team's vision for tooling which requires a certain amount of rigidity. This is one of those cases that probably fell in the gap.

Edit: PropertyDescriptors, IBindingList and some other components of Windows Forms binding are used in WPF too - for example, my MicroModels library relies on PropertyDescriptors to work, and is built for WPF. Silverlight however doesn't support many of these.

I think this is a bug in the WPF toolkit. Check Stack Overflow question ValueMemberPath Binding in AutoCompleteBox WPF only returns top result in last name search?.

I think it has the answer to the problem.

When setting the DataContext in code it is extremely difficult for the designer to determine the type that is being bound to.

When assigning the DataContext in XAML it is much easier and although there is no drop-down in the XAML editor, when you click the little square behind the property name in the properties box you can select the properties.

In addition you can even use a design-time datacontext to add design-time types and data (beta2 related post but still valid)

My guess it is a missing feature of the XAML-editor.