All child elements in fact are properties. To indicate which property accepts the child element as its value you must specify the ContentProperty attribute of the class.
C#
[ContentProperty("PropertyName")] public class SomeClass { ... public PropertyType PropertyName {get;set;} ... } XAML <SomeClass x:Name="someClassInstance"> Value </SomeClass>
[ContentProperty("PropertyName")]
public class SomeClass
{
...
public PropertyType PropertyName {get;set;}
}
<SomeClass x:Name="someClassInstance">
Value
</SomeClass>
This way the last declaration corresponds to the following C# code
C# someClassInstance.PropertyName = Value;
someClassInstance.PropertyName = Value;