MultivalueConverter not called after DragDrop - wpf

Question

I have a IMultivalueConverter which updates the background color of a StackPanel when PropertyA or PropertyB is changed. These Controls are created dynamically.
Problem:
I have added two StackPanels and changed the PropertyA in the code when a button is clicked. This leads to a property changed event.
private void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
if (this.PropertyChanged != null)
{
this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
For the first stackpanel the background color is not updated, but for the second stackpanel this.PropertyChanged inturn calls my MultiValueConverter and background color is updated.
I am not able to understand why only one control is getting updated when both belong to same type and eventhandler is not null.
EDIT:
If I drag and drop a cell value from other control (DevExpress DataGrid) into the first stackpanel and then change the property, the background is not getting updated. It works fine until I drag and drop.
Update:
<StackPanel.Background>
<MultiBinding Converter="{StaticResource ResourceKey=BackgroundColorConverter}">
<Binding Path="PropertyA" UpdateSourceTrigger="PropertyChanged" />
<Binding Path="PropertyB" UpdateSourceTrigger="PropertyChanged" />
</MultiBinding>
</StackPanel.Background>
Update 2:
I have also tried using MultiDataTrigger instead of Converter, but couldn't solve the problem.

Answer 1

Unless i miss understood you, i don't see any complication in doing that,
<Window.Resources>
<app:BackgroundColorConverter x:Key="BackgroundColorConverter"/>
</Window.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<StackPanel Orientation="Horizontal" >
<TextBox Text="{Binding PropertyA}" Width="200"/>
<TextBox Text="{Binding PropertyB}" Width="200"/>
</StackPanel>
<StackPanel Grid.Row="1" Margin="5">
<StackPanel.Background>
<MultiBinding Converter="{StaticResource ResourceKey=BackgroundColorConverter}">
<Binding Path="PropertyA" UpdateSourceTrigger="PropertyChanged" />
<Binding Path="PropertyB" UpdateSourceTrigger="PropertyChanged" />
</MultiBinding>
</StackPanel.Background>
</StackPanel>
<StackPanel Grid.Row="2" Margin="5">
<StackPanel.Background>
<MultiBinding Converter="{StaticResource ResourceKey=BackgroundColorConverter}">
<Binding Path="PropertyA" UpdateSourceTrigger="PropertyChanged" />
<Binding Path="PropertyB" UpdateSourceTrigger="PropertyChanged" />
</MultiBinding>
</StackPanel.Background>
</StackPanel>
</Grid>
the Converter :
public class BackgroundColorConverter:IMultiValueConverter
{
public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
{
if (values==null)
{
return null;
}
return
new SolidColorBrush(Color.FromRgb(byte.Parse(values[0].ToString()), byte.Parse(values[1].ToString()),
50));
}
public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
..And the Code behind
public partial class MainWindow : Window,INotifyPropertyChanged
{
private byte _propertyA ;
private byte _propertyB;
public byte PropertyA
{
get
{
return _propertyA;
}
set
{
if (_propertyA == value)
{
return;
}
_propertyA = value;
OnPropertyChanged();
}
}
public byte PropertyB
{
get
{
return _propertyB;
}
set
{
if (_propertyB == value)
{
return;
}
_propertyB = value;
OnPropertyChanged();
}
}
public MainWindow()
{
InitializeComponent();
this.DataContext = this;
}
public event PropertyChangedEventHandler PropertyChanged;
[NotifyPropertyChangedInvocator]
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
}
let me know if i did miss something

Answer 2

Reason:
When a value is dragged over the StackPanel, I am setting the BackgroundColor manually.
stackpanel.BackGround = new SolidColorBrush(Color.FromArgb(255,255,255,141));
Solution:
When I commented this line, the MultiValue converter is called and BackGround color is updated properly.
I created a property which changes according to DragEnter, DragOver and DragLeave events and then converter is called, I evaluate this value and set the Background color in the converter.