wpf popup not showing on button click - wpf

Question

I have a button and a popup control in it in my xaml as follows:
<Button Grid.Column="0" Grid.Row="5"
HorizontalAlignment="Center"
Margin="88,8,214,0"
Grid.RowSpan="2" Height="26"
VerticalAlignment="Top" Width="22"
IsEnabled="{Binding Path=SearchFound}"
x:Name="cmdPlanList"
Click="cmdPlanList_Click">
<ContentControl>
<Popup IsOpen = "{Binding PlanPopup}"
PlacementTarget = "{Binding ElementName = cmdPlanList}"
AllowsTransparency = "True"
PopupAnimation = "Slide"
x:Name="Popup4Plan">
<Canvas Width = "125"
Height = "100"
Background = "Red" >
<Canvas.RenderTransform>
<RotateTransform x:Name = "theTransform" />
</Canvas.RenderTransform>
<TextBlock TextWrapping = "Wrap"
Foreground = "Blue"
Text = "Hi, this is Popup" />
</Canvas>
</Popup>
</ContentControl>
</Button>
I am setting the DataContext of this Popup from my code-behind as follows:-
My View's code behind:-
using xyz
{
private bool _PlanPopup = false;
public bool PlanPopup
{
get { return _PlanPopup; }
set
{
_PlanPopup = value;
}
}
public MyView()
{
InitializeComponent();
Popup4Plan.DataContext = this;
}
private void cmdPlanList_Click(object sender, RoutedEventArgs e)
{
this.PlanPopup = this.PlanPopup ? false : true;
}
}

Answer 1

If you want to bind the View to a property of itself, make the property a dependency property.
public bool IsOpen
{
get
{
return (bool)GetValue(IsOpenProperty);
}
set
{
SetValue(IsOpenProperty, value);
}
}
public static readonly DependencyProperty IsOpenProperty =
DependencyProperty.Register("IsOpen", typeof(bool), typeof(MyView), new PropertyMetadata(false));
To quickly make it type propdp [tab][tab] and fill in the blanks.
Also:
this.PlanPopup = this.PlanPopup ? false : true;
looks much better this way:
this.PlanPopup = !this.PlanPopup;

Answer 2

For updates on bound properties to work you need to implement INotifyPropertyChanged. For example like the following.
public class XYZ : INotifyPropertyChanged
{
private bool isOpen;
public bool IsOpen {
get { return this.isOpen; }
set {
this.isOpen = value;
this.OnPropertyChanged();
}
}
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
this.PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
With this code an instance of XYZ will notify that the property IsOpen has changed and any bound view elements will re-fetch the value of IsOpen.