WPF: binding to dependency property of a class that inherits a user control base class

Question

I have a user control in wpf named "GoogleMap.xaml/.cs" where the xaml declaration starts like this:

<controls:BaseUserControl x:Class="CompanyNamespace.Controls.GoogleMap"

the code behind:

 public partial class GoogleMap : BaseUserControl{ public static readonly DependencyProperty MapCenterProperty = DependencyProperty.Register("MapCenter", typeof(string), typeof(GoogleMap), new FrameworkPropertyMetadata(string.Empty, OnMapCenterPropertyChanged)); public string MapCenter { get { return (string)GetValue(MapCenterProperty); } set { SetValue(MapCenterProperty, value); } } private static void OnMapCenterPropertyChanged(DependencyObject source, DependencyPropertyChangedEventArgs e){ GoogleMap control = source as GoogleMap; control.SetCenter(e.NewValue.ToString()); } ... }

What's the correct syntax for me to be able to address the property from GoogleMap.xaml:

MapCenter="{Binding Location}"

I can only bind to this property from GoogleMap.xaml if I place the property is in the BaseUserControl class.

Update GoogleMapViewModel.cs

public class GoogleMapViewModel : ContainerViewModel{ private string location; [XmlAttribute("location")] public string Location { get { if (string.IsNullOrEmpty(location)) return appContext.DeviceGeolocation.Location(); return ExpressionEvaluator.Evaluate(location); } set { if (location == value) return; location = value; RaisePropertyChanged("Location"); } }

Since you are inheriting from the base class it shouldn't matter where you put the property. What does your DataContext look like? — Tim Pohlmann
– Tim Pohlmann, Commented Jul 13, 2016 at 14:11
I think it would be better to create a custom control and define its visual in a ControlTemplate. — Yusuf Tarık Günaydın
– Yusuf Tarık Günaydın, Commented Jul 13, 2016 at 14:28

Clemens · Accepted Answer · 2016-07-13 14:34:35Z

In order to bind a UserControl's property in its own XAML, you could declare a Style:

<controls:BaseUserControl x:Class="CompanyNamespace.Controls.GoogleMap" xmlns:local="clr-namespace:CompanyNamespace.Controls" ...> <controls:BaseUserControl.Style> <Style> <Setter Property="local:GoogleMap.MapCenter" Value="{Binding Location}" /> </Style> </controls:BaseUserControl.Style> ... </controls:BaseUserControl>

The XML namespace local is of course redundant if its identical to controls.

You could as well create the Binding in the UserControl's constructor like:

public GoogleMap() { InitializeComponent(); SetBinding(MapCenterProperty, new Binding("Location")); }

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