Binding on DependencyProperty of custom User Control not updating on change

Question

I\'m having difficulties with databinding on my custom user control (s). I created an example project to highlight my problem. I\'m completely new to WPF and essentially MVV

Answer 1

I tried your code works fine the only change i made was to remove the code behind propertychangedcallback you have and databind the Label (Readout) to the dependency property.

USERCONTROL(XAML)

<UserControl x:Class="WpfApplication1.UserControl"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
         mc:Ignorable="d" 
         d:DesignHeight="300" d:DesignWidth="300">
   <Grid>
       <Label Name="Readout" Content="{Binding RelativeSource={RelativeSource 
                            AncestorType=UserControl}, Path=MinutesRemaining}"/>
  </Grid>
</UserControl>

USERCONTROL (CODE BEHIND)

public partial class UserControl1 : UserControl
{
    #region Dependency Properties
    public static readonly DependencyProperty MinutesRemainingProperty =
                DependencyProperty.Register
                (
                    "MinutesRemaining", typeof(int), typeof(UserControl1),
                    new UIPropertyMetadata(10)
                );
    #endregion

    public int MinutesRemaining
    {
        get
        {
            return (int)GetValue(MinutesRemainingProperty);
        }
        set
        {
            SetValue(MinutesRemainingProperty, value);
        }
    }

   public UserControl1()
    {
        InitializeComponent();
    }
}

Answer 2

Your change callback is breaking the binding.

As a skeleton: in your window you have UC.X="{Binding A}" and then in that property change (in UC) you have X=B;. This breaks the binding since in both cases you set X.

To rectify, remove change callback and add this to the label:

 Content="{Binding MinutesRemaining, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}}"