[NonCategorized]
public IList HighlightedItems { get; set; }

<NonCategorized>
Public Property HighlightedItems As IList

<Window
    x:Class="WpfApplication2.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:dxsa="http://schemas.devexpress.com/winfx/2008/xaml/sankey"
    xmlns:local="clr-namespace:WpfApplication2"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    Width="640"
    Height="420"
    mc:Ignorable="d"
    Title="MainWindow">
    <Window.DataContext>
        <local:SankeyViewModel />
    </Window.DataContext>
    <Grid>
        <dxsa:SankeyDiagramControl
            x:Name="sankeyDiagramControl1"
            DataSource="{Binding Data}"
            HighlightedItems="{Binding HighlightedItems}"
            SourceDataMember="Source"
            TargetDataMember="Target"
            WeightDataMember="Value">
            <dxsa:SankeyDiagramControl.Titles>
                <dxsa:SankeyTitle HorizontalAlignment="Center" Content="Export/Import" />
            </dxsa:SankeyDiagramControl.Titles>
        </dxsa:SankeyDiagramControl>
        <Button
            Margin="0,0,140,10"
            HorizontalAlignment="Right"
            VerticalAlignment="Bottom"
            Command="{Binding HighlightCommand}"
            Content="Highlight 'France'" />
        <Label Content="{Binding HighlightedItem}"
            HorizontalAlignment="Right"
            HorizontalContentAlignment="Left"
            VerticalAlignment="Bottom" Margin="0,0,30,10" Width="105"/>

    </Grid>
</Window>

public class SankeyViewModel : ViewModelBase {
    readonly ObservableCollection<object> highlightedItems;

    public object HighlightedItem {
        get {
            string text = string.Empty;
            if(highlightedItems.Count > 0) {
                if(highlightedItems[0] is SankeyItem)
                    text = ((SankeyItem)highlightedItems[0]).Value.ToString();
                else
                    text = highlightedItems[0].ToString();
            }
            else
                text = "(none)";
            return "Current: " + text;
        }
    }
    public ObservableCollection<object> HighlightedItems { get { return highlightedItems; } }
    public DelegateCommand HighlightCommand { get; private set; }
    public List<SankeyItem> Data {
        get { return GetData(); }
    }

    public SankeyViewModel() {
        HighlightCommand = new DelegateCommand(HighlightCommandExecute, HighlightCommandCanExecute);
        highlightedItems = new ObservableCollection<object>();
        highlightedItems.CollectionChanged += HighlightedItems_CollectionChanged;
    }
    void HighlightedItems_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e) {
        RaisePropertyChanged("HighlightedItem");
    }
    bool HighlightCommandCanExecute() {
        return true;
    }
    void HighlightCommandExecute() {
        highlightedItems.Clear();
        highlightedItems.Add("France");
    }
    public List<SankeyItem> GetData() {
        List<SankeyItem> data = new List<SankeyItem>{
            new SankeyItem { Source = "France", Target = "UK", Value = 53 },
            new SankeyItem { Source = "Australia", Target = "UK", Value = 72 },
            new SankeyItem { Source = "France", Target = "Canada", Value = 81 },
            new SankeyItem { Source = "China", Target = "Canada", Value = 96 },
            new SankeyItem { Source = "UK", Target = "France", Value = 61 },
            new SankeyItem { Source = "Canada", Target = "France", Value = 89 }
        };
        return data;
    }
}

public class SankeyItem {
    public string Source { get; set; }
    public string Target { get; set; }
    public double Value { get; set; }
}

Public Class SankeyViewModel
    Inherits ViewModelBase

    Private _HighlightCommand As DelegateCommand
    Private ReadOnly highlightedItemsField As ObservableCollection(Of Object)

    Public ReadOnly Property HighlightedItem As Object
        Get
            Dim text As String = String.Empty

            If highlightedItemsField.Count > 0 Then

                If TypeOf highlightedItemsField(0) Is SankeyItem Then
                    text = CType(highlightedItemsField(CInt(0)), SankeyItem).Value.ToString()
                Else
                    text = highlightedItemsField(0).ToString()
                End If
            Else
                text = "(none)"
            End If

            Return "Current: " & text
        End Get
    End Property

    Public ReadOnly Property HighlightedItems As ObservableCollection(Of Object)
        Get
            Return highlightedItemsField
        End Get
    End Property

    Public Property HighlightCommand As DelegateCommand
        Get
            Return _HighlightCommand
        End Get
        Private Set(ByVal value As DelegateCommand)
            _HighlightCommand = value
        End Set
    End Property

    Public ReadOnly Property Data As List(Of SankeyItem)
        Get
            Return GetData()
        End Get
    End Property

    Public Sub New()
        HighlightCommand = New DelegateCommand(AddressOf HighlightCommandExecute, AddressOf HighlightCommandCanExecute)
        highlightedItemsField = New ObservableCollection(Of Object)()
        Me.highlightedItemsField.CollectionChanged += AddressOf HighlightedItems_CollectionChanged
    End Sub

    Private Sub HighlightedItems_CollectionChanged(ByVal sender As Object, ByVal e As NotifyCollectionChangedEventArgs)
        RaisePropertyChanged("HighlightedItem")
    End Sub

    Private Function HighlightCommandCanExecute() As Boolean
        Return True
    End Function

    Private Sub HighlightCommandExecute()
        highlightedItemsField.Clear()
        highlightedItemsField.Add("France")
    End Sub

    Public Function GetData() As List(Of SankeyItem)
        Dim data As List(Of SankeyItem) = New List(Of SankeyItem) From {
            New SankeyItem With {
                .Source = "France",
                .Target = "UK",
                .Value = 53
            },
            New SankeyItem With {
                .Source = "Australia",
                .Target = "UK",
                .Value = 72
            },
            New SankeyItem With {
                .Source = "France",
                .Target = "Canada",
                .Value = 81
            },
            New SankeyItem With {
                .Source = "China",
                .Target = "Canada",
                .Value = 96
            },
            New SankeyItem With {
                .Source = "UK",
                .Target = "France",
                .Value = 61
            },
            New SankeyItem With {
                .Source = "Canada",
                .Target = "France",
                .Value = 89
            }
        }
        Return data
    End Function
End Class

Public Class SankeyItem
    Public Property Source As String
    Public Property Target As String
    Public Property Value As Double
End Class