Dragable objects in WPF in an ItemsControl?

Question

I want to be able to implement an ItemsControl with dragable items. The reason for the ItemsControl is so I can bind to my ViewModel in the background.

I\'ve tried

Answer 1

Ben I didn't think that approach worked at first but after more experimenting I got it.

The problem could be boiled down to: Canvas.Top and Canvas.Left don't work while in an items control. But you are correct that the style is the way to get around the problem. Here is the solution I came up with:

<ItemsControl ItemsSource="{Binding Notes}">
        <ItemsControl.ItemsPanel>
            <ItemsPanelTemplate>
                <Canvas />
            </ItemsPanelTemplate>
        </ItemsControl.ItemsPanel>
        <ItemsControl.ItemTemplate>
            <DataTemplate>
                <Thumb Width="150" Height="150" DragDelta="Thumb_DragDelta" />
            </DataTemplate>
        </ItemsControl.ItemTemplate>
        <ItemsControl.ItemContainerStyle>
            <Style>
                <Setter Property="Canvas.Left" Value="{Binding X}" />
                <Setter Property="Canvas.Top" Value="{Binding Y}" />
            </Style>
        </ItemsControl.ItemContainerStyle>
    </ItemsControl>

And the codebehind:

 public partial class MainWindow : Window
{
    public ObservableCollection<Note> Notes { get; set; }

    public MainWindow()
    {
        InitializeComponent();

        DataContext = this;

        Notes = new ObservableCollection<Note>();
        Notes.Add(new Note(){Title="test", X=100, Y=0});
    }

    private void Thumb_DragDelta(object sender, System.Windows.Controls.Primitives.DragDeltaEventArgs e)
    {
        Note n = (Note)((FrameworkElement)sender).DataContext;
        n.X += e.HorizontalChange;
        n.Y += e.VerticalChange;
    }
}

public class Note : INotifyPropertyChanged
{
    private string title;
    private double x;
    private double y;

    public double Y
    {
        get { return y; }
        set
        {
            y = value;
            if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("Y"));
        }
    }

    public double X
    {
        get { return x; }
        set
        {
            x = value;
            if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("X"));
        }
    }


    public string Title
    {
        get { return title; }
        set
        {
            title = value;
            if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("Title"));
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

Answer 2

Try setting up the Canvas binding properties via a style

<Style x:Key="ThumbStyle">
  <Setter Property="Canvas.Left" Value="{Binding Path=Left}"/>
  <Setter Property="Canvas.Top" Value="{Binding Path=Top}"/>
  <!-- more if required -->

</Style>

Then the thumb becomes:

<Thumb Style={StaticResource ThumbStyle}" ... />