WPF

<Label Grid.Row="0" Content="Files to be copied..." Background="{x:Null}" Foreground="White" HorizontalAlignment="Center"/>
        <ListBox Grid.Row="1"
                 x:Name="dropList"
                 Margin="10"
                 SelectionMode="Extended"
                 AllowDrop="True" 
                 Drop="DropList_Drop" 
                 Foreground="White"
                 Background="#FF333337"
                 Height="Auto"
                 Width="Auto"
                 VerticalAlignment="Stretch"
                 MouseMove="DropList_MouseMove"
                 PreviewDragLeave="DropList_PreviewDragLeave" >            
            <ListBox.ContextMenu>
                <ContextMenu>
                    <MenuItem x:Name="Options"
                              Header="Options..."
                              Click="Options_Click"
                              Foreground="Black"/>
                </ContextMenu>
            </ListBox.ContextMenu>
        </ListBox>  

private void DropList_Drop(object sender, DragEventArgs e)
        {            
            if (e.Data.GetDataPresent(DataFormats.FileDrop))
            {
                string[] files = (string[])e.Data.GetData(DataFormats.FileDrop);
                foreach (string data in files)
                {
                    if (!dropList.Items.Contains(data))
                        dropList.Items.Add(data);
                }
            }
            else
            {
                object data = e.Data.GetData(typeof(string));
                dragSource.Items.Remove(data);
                dropList.Items.Add(data);
            }
        }

        private void DropList_MouseMove(object sender, MouseEventArgs e)
        {
            // Get the current mouse position
            Point mousePos = e.GetPosition(null);
            Vector diff = startPoint - mousePos;

            if (e.LeftButton == MouseButtonState.Pressed &&
                (Math.Abs(diff.X) > SystemParameters.MinimumHorizontalDragDistance ||
                Math.Abs(diff.Y) > SystemParameters.MinimumVerticalDragDistance))
            {
                dragSource = dropList;
                object data = GetDataFromListBox(dragSource, e.GetPosition(dropList));

                if (data != null)
                {
                    DragDrop.DoDragDrop(dropList, data, DragDropEffects.Move);
                }
            }
        }

        private void DropList_PreviewDragLeave(object sender, DragEventArgs e)
        {
            if (Mouse.LeftButton == MouseButtonState.Released)
            {
                dragSource = dropList;
                object data = GetDataFromListBox(dragSource, e.GetPosition(dropList));

                if (data != null && dropList.Items.Contains(data))
                    dropList.Items.Remove(data);
            }            
        }

    <Window.Resources>
        <SolidColorBrush x:Key="normalColor">#0026FF</SolidColorBrush>
        <SolidColorBrush x:Key="hoverColor">#E62DFF</SolidColorBrush>
        <SolidColorBrush x:Key="pressedColor">#7F7818</SolidColorBrush>
        <SolidColorBrush x:Key="disabledColor">#808080</SolidColorBrush>
        <Geometry x:Key="settingsIconOutter">
            M911 2215 c-34 -39 -36 -45 -54 -153 l-12 -73 -70 -30 -70 -29 -40
            29 c-106 76 -117 81 -167 81 -67 0 -89 -14 -195 -122 -127 -130 -134 -176 -43
            -305 28 -39 50 -74 50 -78 0 -4 -12 -38 -26 -75 l-27 -68 -51 -7 c-106 -14
            -146 -26 -176 -57 l-30 -30 0 -177 0 -177 28 -26 c40 -38 59 -45 151 -59 58
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            -168 0 -67 14 -89 122 -195 131 -128 177 -134 309 -40 l74 53 65 -27 c72 -30
            72 -30 91 -149 10 -63 17 -80 44 -107 l33 -33 177 0 178 0 32 35 c27 28 35 47
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            76 11 32 16 186 169 203 201 8 15 14 51 14 81 0 48 -5 61 -54 131 l-54 77 28
            67 c32 74 31 74 150 93 63 10 80 17 107 44 l33 33 0 177 0 177 -33 33 c-26 26
            -45 34 -102 44 -116 19 -126 22 -132 39 -3 10 -16 40 -28 69 l-23 51 49 69
            c96 133 90 184 -40 316 -47 49 -98 95 -113 103 -15 8 -51 14 -80 14 -49 0 -61
            -5 -132 -55 l-78 -54 -37 18 c-20 10 -52 24 -72 30 -34 11 -37 15 -43 64 -15
            107 -27 147 -58 177 l-30 30 -178 0 -178 0 -31 -35z m309 -111 c0 -34 35 -204
            46 -221 8 -13 40 -30 81 -43 37 -13 94 -36 125 -51 32 -16 68 -29 81 -29 13 0
            61 27 107 60 46 33 86 60 89 60 4 0 36 -29 71 -65 49 -50 62 -69 55 -80 -93
            -135 -115 -170 -115 -186 0 -11 13 -45 29 -77 15 -31 38 -87 50 -124 12 -36
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            -9 -29 -32 -84 -50 -124 -19 -40 -34 -81 -34 -92 0 -10 28 -60 62 -111 l62
            -91 -67 -66 -66 -67 -90 62 c-49 34 -99 62 -110 62 -12 0 -47 -13 -79 -29 -31
            -15 -87 -38 -124 -50 -36 -12 -71 -28 -76 -34 -6 -7 -18 -53 -27 -102 -8 -50
            -18 -100 -21 -112 -4 -22 -9 -23 -99 -23 -109 0 -94 -16 -120 134 -8 48 -19
            94 -25 102 -7 7 -35 21 -63 30 -29 9 -81 30 -116 45 -93 42 -113 39 -213 -30
            l-85 -60 -67 68 -68 68 61 85 c70 97 75 125 37 191 -13 23 -37 77 -52 120 -15
            43 -34 82 -43 86 -9 5 -64 17 -124 26 l-107 18 0 97 0 97 109 18 c124 20 139
            30 160 105 7 25 28 78 48 118 24 52 32 82 28 100 -3 15 -33 63 -65 107 l-59
            80 69 69 68 69 69 -50 c116 -84 136 -89 206 -49 23 13 77 37 120 52 43 15 82
            34 86 43 5 9 17 64 27 124 l18 107 98 0 c54 0 98 -3 98 -6z
        </Geometry>
        <Geometry x:Key="settingsIconInner">
            M970 1601 c-154 -49 -279 -176 -324 -330 -25 -84 -21 -230 7 -311 73
            -206 247 -330 462 -330 153 1 245 34 345 126 71 66 111 128 140 214 29 87 25
            256 -9 339 -58 144 -177 253 -320 295 -75 22 -229 20 -301 -3z m293 -164 c71
            -32 141 -102 175 -175 38 -81 38 -193 0 -274 -34 -73 -103 -142 -176 -176 -81
            -38 -193 -38 -274 0 -73 34 -142 103 -176 176 -36 76 -38 192 -5 265 85 184
            282 264 456 184z
        </Geometry>
        <Style TargetType="{x:Type Button}"
               x:Key="settingsButton">
            <Setter Property="Height" Value="120"/>
            <Setter Property="Width" Value="120"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate>
                        <Viewbox>
                            <Grid>
                                <Path x:Name="outerPath" Data="{StaticResource settingsIconOutter}" Fill="{StaticResource normalColor}" />
                                <Path x:Name="innerPath" Data="{StaticResource settingsIconInner}" Fill="{StaticResource normalColor}" />
                            </Grid>
                        </Viewbox>
                        <ControlTemplate.Triggers>
                            <Trigger Property="Button.IsMouseOver" Value="true">
                                <Setter TargetName="outerPath" Property="Fill" Value="{StaticResource hoverColor}" />
                                <Setter TargetName="innerPath" Property="Fill" Value="{StaticResource hoverColor}" />
                            </Trigger>
                            <Trigger Property="Button.IsPressed" Value="true">
                                <Setter TargetName="outerPath" Property="Fill" Value="{StaticResource pressedColor}" />
                                <Setter TargetName="innerPath" Property="Fill" Value="{StaticResource pressedColor}" />
                            </Trigger>
                            <Trigger Property="Button.IsEnabled" Value="false">
                                <Setter TargetName="outerPath" Property="Fill" Value="{StaticResource disabledColor}" />
                                <Setter TargetName="innerPath" Property="Fill" Value="{StaticResource disabledColor}" />
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </Window.Resources>
    <StackPanel Orientation="Horizontal"
                HorizontalAlignment="Center">

<pre>
    <Button Style="{StaticResource settingsButton}"/>

    <Button Style="{StaticResource settingsButton}"
            IsEnabled="False"
            Margin="20,0,0,0"/>

public class PurchaseOrderEntity : _EntityBase
{
    private int _Quantity;
    public int Quantity
    {
        get { return _Quantity; }
        set
        {
            if (_Quantity != value)
            {
                _Quantity = value;
                RaisePropertyChanged("Quantity");
            }
        }
    }

    private int _SizeId;
    public int SizeId
    {
        get { return _SizeId; }
        set
        {
            if (_SizeId != value)
            {
                _SizeId = value;
                RaisePropertyChanged("SizeId");
            }
        }
    }

}

private List<PurchaseOrderEntity> _PurchaseOrders;
public List<PurchaseOrderEntity> PurchaseOrders
{
    get { return _PurchaseOrders; }
    set
    {
        if (_PurchaseOrders != value)
        {
            _PurchaseOrders = value;
            RaisePropertyChanged("PurchaseOrders");
        }
    }
}

private PurchaseOrderEntity _SelectedPurchaseOrder;
public PurchaseOrderEntity SelectedPurchaseOrder
{
    get { return _SelectedPurchaseOrder; }
    set
    {
        if (_SelectedPurchaseOrder != value)
        {
            _SelectedPurchaseOrder = value;
            RaisePropertyChanged("SelectedPurchaseOrder");
        }
    }
}

<DataGrid Grid.Row="2"
            Margin="5"
            x:Name="lumberGrid"
            ItemsSource="{Binding PurchaseOrders}"
            SelectedItem="{Binding SelectedPurchaseOrder, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
            HorizontalGridLinesBrush="LightGray"
            VerticalGridLinesBrush="LightGray"
            AutoGenerateColumns="False"
            CanUserAddRows="True"
            CanUserDeleteRows="True"
            CanUserReorderColumns="False"
            CanUserResizeColumns="False"
            CanUserSortColumns="False"
            BorderBrush="SteelBlue"
            BorderThickness="1"
            HorizontalScrollBarVisibility="Auto"
            VerticalScrollBarVisibility="Auto"
            VerticalAlignment="Stretch">

<pre>
<DataGrid.Columns>

    <DataGridTextColumn Header="Quantity" 
                        Binding="{Binding Quantity, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
                        Width="85"/>

    <DataGridTemplateColumn Header="Size"
                            Width="85">
        <DataGridTemplateColumn.CellTemplate>
            <DataTemplate>
                <ComboBox ItemsSource="{Binding Path=DataContext.LumberSizes, RelativeSource={RelativeSource AncestorType={x:Type Window}}}"
                            DisplayMemberPath="Caption"
                            SelectedValuePath="Id"
                            SelectedValue="{Binding SizeId, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>

            </DataTemplate>
        </DataGridTemplateColumn.CellTemplate>
    </DataGridTemplateColumn>

</DataGrid.Columns>

System.Windows.Data Error: 23 : Cannot convert '{NewItemPlaceholder}' from type 'NamedObject' to type 'Jayhawk.Entities.PurchaseOrderEntity' for 'en-US' culture with default conversions; consider using Converter property of Binding. NotSupportedException:'System.NotSupportedException: TypeConverter cannot convert from MS.Internal.NamedObject.
   at System.ComponentModel.TypeConverter.GetConvertFromException(Object value)
   at System.ComponentModel.TypeConverter.ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, Object value)
   at MS.Internal.Data.DefaultValueConverter.ConvertHelper(Object o, Type destinationType, DependencyObject targetElement, CultureInfo culture, Boolean isForward)'

   System.Windows.Data Error: 7 : ConvertBack cannot convert value '{NewItemPlaceholder}' (type 'NamedObject'). BindingExpression:Path=SelectedPurchaseOrder; DataItem='AddEditPOViewModel' (HashCode=11892013); target element is 'DataGrid' (Name='lumberGrid'); target property is 'SelectedItem' (type 'Object') NotSupportedException:'System.NotSupportedException: TypeConverter cannot convert from MS.Internal.NamedObject.
   at MS.Internal.Data.DefaultValueConverter.ConvertHelper(Object o, Type destinationType, DependencyObject targetElement, CultureInfo culture, Boolean isForward)
   at MS.Internal.Data.ObjectTargetConverter.ConvertBack(Object o, Type type, Object parameter, CultureInfo culture)
   at System.Windows.Data.BindingExpression.ConvertBackHelper(IValueConverter converter, Object value, Type sourceType, Object parameter, CultureInfo culture)'

public partial class MainWindow : Window
    {
        ItemList il;
        GroupList gl;

        public MainWindow()
        {
            InitializeComponent();
        }
        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            il = new ItemList();
            ICollectionView cvs = CollectionViewSource.GetDefaultView(il);
            cvs.SortDescriptions.Add(new SortDescription("_type", ListSortDirection.Ascending));
            cvs.SortDescriptions.Add(new SortDescription("_name", ListSortDirection.Ascending));
            cvs.GroupDescriptions.Add(new PropertyGroupDescription("_type"));
            ListBox2.ItemsSource = cvs;

            gl = new GroupList();
            ICollectionView cvt = CollectionViewSource.GetDefaultView(gl);
            ListBox1.ItemsSource = cvt;
        } 
    }

    public class Item
    {
        public string _type { get; set; }
        public string _name { get; set; }
        public Item()
        {
        }
    }
    public class ItemList : ObservableCollection<Item> {
        public ItemList() {
            base.Add(new Item() { _type = "fruit", _name = "apple" });
            base.Add(new Item() { _type = "vegetable", _name = "potato" });
            base.Add(new Item() { _type = "fruit", _name = "banana" });
            base.Add(new Item() { _type = "vegetable", _name = "tomato" });
            base.Add(new Item() { _type = "fruit", _name = "pear" });
            base.Add(new Item() { _type = "vegetable", _name = "salad" });
            base.Add(new Item() { _type = "fruit", _name = "orange" });
            base.Add(new Item() { _type = "vegetable", _name = "onion" }); 
        }
    }

    public class Group
    {
        public string _groupname { get; set; }
        public List<String> _members { get; set; }
        public string _recipe { get; set; }
        public Group()
        {
        }
    }
    public class GroupList : ObservableCollection<Group>
    {
        public GroupList()
        {
            base.Add(new Group() { _groupname = "Group_1", _members = new List<String>() { "apple", "salad" }, _recipe = "Do this and do that" });
            base.Add(new Group() { _groupname = "Group_2", _members = new List<String>() { "banana", "onion" }, _recipe = "Don't do that and do this" });
        }
    }

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525"
        Loaded="Window_Loaded">
    <Grid>
        <Label Margin="12,0,378,283" Content="Group"></Label>
        <Label Margin="190,0,200,283" Content="Members"></Label>
        <Label Margin="309,0,81,283" Content="Recipe"></Label>
        <TextBox Margin="309,34,12,12" DataContext="{Binding SelectedItem, ElementName=ListBox1}" Text="{Binding Path=_recipe, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"></TextBox>
        <ListBox Margin="12,34,378,12" Name="ListBox1" SelectionMode="Single">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <TextBlock Text="{Binding _groupname}" />
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
        <ListBox Margin="190,34,199,12" Name="ListBox2" SelectionMode="Multiple" SelectedValuePath="_name">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <TextBlock Text="{Binding _name}" />
                </DataTemplate>
            </ListBox.ItemTemplate>
            <ListBox.GroupStyle>
                <GroupStyle>
                    <GroupStyle.ContainerStyle>
                        <Style TargetType="{x:Type GroupItem}">
                            <Setter Property="Template">
                                <Setter.Value>
                                    <ControlTemplate>
                                        <Expander Header="{Binding Name}" IsExpanded="True">
                                            <ItemsPresenter />
                                        </Expander>
                                    </ControlTemplate>
                                </Setter.Value>
                            </Setter>
                        </Style>
                    </GroupStyle.ContainerStyle>
                </GroupStyle>
            </ListBox.GroupStyle>
        </ListBox>
    </Grid>
</Window>

System.Windows.Controls.DataVisualization.Charting

<chart:Chart
                    Name="PerfChart"
                    Grid.Row="1"
                    HorizontalAlignment="Stretch"
                    Margin="0,0,0,0"
                    Title="Chart Title"
                    VerticalAlignment="Stretch"
                    Height="Auto" Width="Auto"
               >
    <chart:Chart.LegendStyle>
        <Style TargetType="dv:Legend">
            <Setter Property="VerticalAlignment" Value="Top"></Setter>
            <Setter Property="HorizontalAlignment" Value="Center"></Setter>
        </Style>
    </chart:Chart.LegendStyle>

</chart:Chart>

public void LoadLineChartData()
{

    Dictionary<Date,double> cbHist =
        Controller.CostBasisHistory(strDate, endDate, finInstFilter, port);
    List < KeyValuePair<DateTime, double> > cbList = new List<KeyValuePair<DateTime, double>>();
    foreach(Date dt in cbHist.Keys)
    {
        cbList.Add(new KeyValuePair<DateTime, double>(dt.ToDateTime(),cbHist[dt]) );
    }


    Style pointStyle = new Style(typeof(Control));


    LineSeries series1 = new LineSeries();

    series1.DependentValuePath = "Value";
    series1.IndependentValuePath = "Key";
    series1.Title = "Cost Basis";
    series1.DataPointStyle = pointStyle;
    series1.ItemsSource = cbList;


    PerfChart.Series.Clear();
    PerfChart.Series.Add(series1);
}

<pre>public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();


        string path1 = @"d:\\root\\sounds\\";   /*Environment.GetFolderPath(Environment.SpecialFolder.Desktop);*/
        string[] files = Directory.GetFiles(path1, "*.*", SearchOption.AllDirectories);
        string[] dir = Directory.GetDirectories(path1);
        string result;





        foreach (string sFile in files)
        { 
            Button nwbut = new Button();
            result = System.IO.Path.GetFileNameWithoutExtension(sFile);
            nwbut.Content = result;
            nwbut.Height = 30;
            nwbut.Width = 80;
            nwbut.Margin = Margin = new Thickness(5, 5, 5, 5);
            nwbut.Click += (s, e) => { mediaElement2.Source = new Uri(sFile); };
            WrapPanel wp = new WrapPanel();
            wp.Children.Add(nwbut);

            Grid gr = new Grid();
            gr.Children.Add(wp);
            TabItem ti = new TabItem();
            ti.Content = gr;

                foreach  (string header in dir)
                    ti.Header = System.IO.Path.GetFileNameWithoutExtension(header);
                    tc.Items.Add(ti);

        }
   }
}
}