问如何创建类似于wpf中evernote的标记控件？

EN

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:WpfApplication1"
        xmlns:s="clr-namespace:System;assembly=mscorlib"
        Title="MainWindow" Height="350" Width="525">

    <Window.DataContext>
        <local:ViewModel />
    </Window.DataContext>

    <Grid>
        <!-- todo: implement ICommand properties on EvernoteTagControl to allow easy binding to the viewmodel. Alternatively, the user could use a behavior to handle TagClick, and if necessary TagAdded/TagRemoved -->
        <local:EvernoteTagControl ItemsSource="{Binding SelectedTags}" TagClick="TagControl_TagClick" >
            <local:EvernoteTagControl.AllTags>
                <s:String>read</s:String>
                <s:String>receipt</s:String>
                <s:String>recipe</s:String>
                <s:String>research</s:String>
                <s:String>restaurants</s:String>
            </local:EvernoteTagControl.AllTags>
        </local:EvernoteTagControl>
    </Grid>
</Window>

using System.Collections.Generic;
using System.ComponentModel;

namespace WpfApplication1
{
    public class ViewModel : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

        private List<EvernoteTagItem> _selectedTags = new List<EvernoteTagItem>();
        public List<EvernoteTagItem> SelectedTags
        {
            get { return _selectedTags; }
            set
            {
                _selectedTags = value;
                if (_selectedTags != value)
                    OnPropertyChanged("SelectedTags");
            }
        }

        public ViewModel()
        {
            this.SelectedTags = new List<EvernoteTagItem>() { new EvernoteTagItem("news"), new EvernoteTagItem("priority") };
        }

        private void OnPropertyChanged(string propertyName)
        {
            if (this.PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

using System;
using System.Collections;
using System.Collections.Generic;
using System.Windows;
using System.Windows.Controls;

namespace WpfApplication1
{
    [TemplatePart(Name = "PART_CreateTagButton", Type = typeof(Button))]
    public class EvernoteTagControl : ListBox
    {
        public event EventHandler<EvernoteTagEventArgs> TagClick;
        public event EventHandler<EvernoteTagEventArgs> TagAdded;
        public event EventHandler<EvernoteTagEventArgs> TagRemoved;

        static EvernoteTagControl()
        {
            // lookless control, get default style from generic.xaml
            DefaultStyleKeyProperty.OverrideMetadata(typeof(EvernoteTagControl), new FrameworkPropertyMetadata(typeof(EvernoteTagControl)));
        }

        public EvernoteTagControl()
        {
            //// some dummy data, this needs to be provided by user
            //this.ItemsSource = new List<EvernoteTagItem>() { new EvernoteTagItem("receipt"), new EvernoteTagItem("restaurant") };
            //this.AllTags = new List<string>() { "recipe", "red" };
        }

        // AllTags
        public List<string> AllTags { get { return (List<string>)GetValue(AllTagsProperty); } set { SetValue(AllTagsProperty, value); } }
        public static readonly DependencyProperty AllTagsProperty = DependencyProperty.Register("AllTags", typeof(List<string>), typeof(EvernoteTagControl), new PropertyMetadata(new List<string>()));


        // IsEditing, readonly
        public bool IsEditing { get { return (bool)GetValue(IsEditingProperty); } internal set { SetValue(IsEditingPropertyKey, value); } }
        private static readonly DependencyPropertyKey IsEditingPropertyKey = DependencyProperty.RegisterReadOnly("IsEditing", typeof(bool), typeof(EvernoteTagControl), new FrameworkPropertyMetadata(false));
        public static readonly DependencyProperty IsEditingProperty = IsEditingPropertyKey.DependencyProperty;

        public override void OnApplyTemplate()
        {
            Button createBtn = this.GetTemplateChild("PART_CreateTagButton") as Button;
            if (createBtn != null)
                createBtn.Click += createBtn_Click;

            base.OnApplyTemplate();
        }

        /// <summary>
        /// Executed when create new tag button is clicked.
        /// Adds an EvernoteTagItem to the collection and puts it in edit mode.
        /// </summary>
        void createBtn_Click(object sender, RoutedEventArgs e)
        {
            var newItem = new EvernoteTagItem() { IsEditing = true };
            AddTag(newItem);
            this.SelectedItem = newItem;
            this.IsEditing = true;

        }

        /// <summary>
        /// Adds a tag to the collection
        /// </summary>
        internal void AddTag(EvernoteTagItem tag)
        {
            if (this.ItemsSource == null)
                this.ItemsSource = new List<EvernoteTagItem>();

            ((IList)this.ItemsSource).Add(tag); // assume IList for convenience
            this.Items.Refresh();

            if (TagAdded != null)
                TagAdded(this, new EvernoteTagEventArgs(tag));
        }

        /// <summary>
        /// Removes a tag from the collection
        /// </summary>
        internal void RemoveTag(EvernoteTagItem tag, bool cancelEvent = false)
        {
            if (this.ItemsSource != null)
            {
                ((IList)this.ItemsSource).Remove(tag); // assume IList for convenience
                this.Items.Refresh();

                if (TagRemoved != null && !cancelEvent)
                    TagRemoved(this, new EvernoteTagEventArgs(tag));
            }
        }


        /// <summary>
        /// Raises the TagClick event
        /// </summary>
        internal void RaiseTagClick(EvernoteTagItem tag)
        {
            if (this.TagClick != null)
                TagClick(this, new EvernoteTagEventArgs(tag));
        }
    }

    public class EvernoteTagEventArgs : EventArgs
    {
        public EvernoteTagItem Item { get; set; }

        public EvernoteTagEventArgs(EvernoteTagItem item)
        {
            this.Item = item;
        }
    }
}

using System.Collections;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;

namespace WpfApplication1
{
    [TemplatePart(Name = "PART_InputBox", Type = typeof(AutoCompleteBox))]
    [TemplatePart(Name = "PART_DeleteTagButton", Type = typeof(Button))]
    [TemplatePart(Name = "PART_TagButton", Type = typeof(Button))]
    public class EvernoteTagItem : Control
    {

        static EvernoteTagItem()
        {
            // lookless control, get default style from generic.xaml
            DefaultStyleKeyProperty.OverrideMetadata(typeof(EvernoteTagItem), new FrameworkPropertyMetadata(typeof(EvernoteTagItem)));
        }

        public EvernoteTagItem() { }
        public EvernoteTagItem(string text)
            : this()
        {
            this.Text = text;
        }

        // Text
        public string Text { get { return (string)GetValue(TextProperty); } set { SetValue(TextProperty, value); } }
        public static readonly DependencyProperty TextProperty = DependencyProperty.Register("Text", typeof(string), typeof(EvernoteTagItem), new PropertyMetadata(null));

        // IsEditing, readonly
        public bool IsEditing { get { return (bool)GetValue(IsEditingProperty); } internal set { SetValue(IsEditingPropertyKey, value); } }
        private static readonly DependencyPropertyKey IsEditingPropertyKey = DependencyProperty.RegisterReadOnly("IsEditing", typeof(bool), typeof(EvernoteTagItem), new FrameworkPropertyMetadata(false));
        public static readonly DependencyProperty IsEditingProperty = IsEditingPropertyKey.DependencyProperty;

        /// <summary>
        /// Wires up delete button click and focus lost 
        /// </summary>
        public override void OnApplyTemplate()
        {
            AutoCompleteBox inputBox = this.GetTemplateChild("PART_InputBox") as AutoCompleteBox;
            if (inputBox != null)
            {
                inputBox.LostFocus += inputBox_LostFocus;
                inputBox.Loaded += inputBox_Loaded;
            }

            Button btn = this.GetTemplateChild("PART_TagButton") as Button;
            if (btn != null)
            {
                btn.Loaded += (s, e) =>
                {
                    Button b = s as Button;
                    var btnDelete = b.Template.FindName("PART_DeleteTagButton", b) as Button; // will only be found once button is loaded
                    if (btnDelete != null)
                    {
                        btnDelete.Click -= btnDelete_Click; // make sure the handler is applied just once
                        btnDelete.Click += btnDelete_Click;
                    }
                };

                btn.Click += (s, e) =>
                {
                    var parent = GetParent();
                    if (parent != null)
                        parent.RaiseTagClick(this); // raise the TagClick event of the EvernoteTagControl
                };
            }

            base.OnApplyTemplate();
        }

        /// <summary>
        /// Handles the click on the delete glyph of the tag button.
        /// Removes the tag from the collection.
        /// </summary>
        void btnDelete_Click(object sender, RoutedEventArgs e)
        {

            var item = FindUpVisualTree<EvernoteTagItem>(sender as FrameworkElement);
            var parent = GetParent();
            if (item != null && parent != null)
                parent.RemoveTag(item);

            e.Handled = true; // bubbling would raise the tag click event
        }

        /// <summary>
        /// When an AutoCompleteBox is created, set the focus to the textbox.
        /// Wire PreviewKeyDown event to handle Escape/Enter keys
        /// </summary>
        /// <remarks>AutoCompleteBox.Focus() is broken: http://stackoverflow.com/questions/3572299/autocompletebox-focus-in-wpf</remarks>
        void inputBox_Loaded(object sender, RoutedEventArgs e)
        {
            AutoCompleteBox acb = sender as AutoCompleteBox;
            if (acb != null)
            {
                var tb = acb.Template.FindName("Text", acb) as TextBox;
                if (tb != null)
                    tb.Focus();

                // PreviewKeyDown, because KeyDown does not bubble up for Enter
                acb.PreviewKeyDown += (s, e1) =>
                {
                    var parent = GetParent();
                    if (parent != null)
                    {
                        switch (e1.Key)
                        {
                            case (Key.Enter):  // accept tag
                                parent.Focus(); 
                                break;
                            case (Key.Escape): // reject tag
                                parent.Focus();
                                parent.RemoveTag(this, true); // do not raise RemoveTag event
                                break;
                        }
                    }
                };
            }
        }

        /// <summary>
        /// Set IsEditing to false when the AutoCompleteBox loses keyboard focus.
        /// This will change the template, displaying the tag as a button.
        /// </summary>
        void inputBox_LostFocus(object sender, RoutedEventArgs e)
        {
            this.IsEditing = false;
            var parent = GetParent();
            if (parent != null)
                parent.IsEditing = false;
        }

        private EvernoteTagControl GetParent()
        {
            return FindUpVisualTree<EvernoteTagControl>(this);
        }

        /// <summary>
        /// Walks up the visual tree to find object of type T, starting from initial object
        /// http://www.codeproject.com/Tips/75816/Walk-up-the-Visual-Tree
        /// </summary>
        private static T FindUpVisualTree<T>(DependencyObject initial) where T : DependencyObject
        {
            DependencyObject current = initial;
            while (current != null && current.GetType() != typeof(T))
            {
                current = VisualTreeHelper.GetParent(current);
            }
            return current as T;
        }
    }
}

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                            xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                            xmlns:local="clr-namespace:WpfApplication1"
                            xmlns:tkInput="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Input.Toolkit">

    <SolidColorBrush x:Key="HighlightBrush" Color="DodgerBlue" />

    <!-- EvernoteTagControl default style -->
    <Style TargetType="{x:Type local:EvernoteTagControl}">
        <Style.Resources>
            <SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" Color="White"/>
            <SolidColorBrush x:Key="{x:Static SystemColors.ControlBrushKey}" Color="White" />
            <LinearGradientBrush x:Key="IconBrush" EndPoint="0,1">
                <GradientStop Color="#5890f0" Offset="0" />
                <GradientStop Color="#0351d7" Offset="1" />
            </LinearGradientBrush>
        </Style.Resources>
        <Setter Property="FocusVisualStyle" Value="{x:Null}" />
        <Setter Property="VerticalAlignment" Value="Top" />
        <Setter Property="Margin" Value="5" />
        <Setter Property="MinHeight" Value="25" />
        <Setter Property="VerticalContentAlignment" Value="Center" />
        <Setter Property="SnapsToDevicePixels" Value="True" />
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type local:EvernoteTagControl}">
                    <Grid>
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="Auto" />
                            <ColumnDefinition Width="Auto" />
                            <ColumnDefinition Width="Auto" />
                        </Grid.ColumnDefinitions>
                        <Path Grid.Column="0" Margin="2" Fill="{StaticResource IconBrush}" Height="19" Stretch="Uniform" Data="M 50.535714,0.44196425 0.00446427,34.754464 l 0,106.906246 100.71874573,0 0,-107.124996 L 50.535714,0.44196425 z m 0.1875,21.21874975 c 6.311826,0 11.40625,5.094424 11.40625,11.40625 0,6.311826 -5.094424,11.4375 -11.40625,11.4375 -6.311826,0 -11.4375,-5.125674 -11.4375,-11.4375 0,-6.311826 5.125674,-11.40625 11.4375,-11.40625 z" />
                        <ItemsPresenter Grid.Column="1"  />
                        <Button Margin="5,0,0,0" Grid.Column="2" Content="Click to add tag..." x:Name="PART_CreateTagButton">
                            <Button.Template>
                                <ControlTemplate TargetType="Button">
                                    <ContentPresenter TextElement.Foreground="#FF555555" VerticalAlignment="Center" />
                                    <ControlTemplate.Triggers>
                                        <Trigger Property="IsMouseOver" Value="True">
                                            <Setter Property="Cursor" Value="Hand" />
                                        </Trigger>
                                    </ControlTemplate.Triggers>
                                </ControlTemplate>
                            </Button.Template>
                        </Button>
                    </Grid>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsEditing" Value="True">
                            <Setter TargetName="PART_CreateTagButton" Property="Visibility" Value="Collapsed" />
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
        <Setter Property="ItemContainerStyle">
            <Setter.Value>
                <Style TargetType="{x:Type ListBoxItem}">
                    <Setter Property="FocusVisualStyle" Value="{x:Null}" />
                </Style>
            </Setter.Value>
        </Setter>
        <Setter Property="ItemsPanel" >
            <Setter.Value>
                <ItemsPanelTemplate>
                    <StackPanel Orientation="Horizontal" />
                </ItemsPanelTemplate>
            </Setter.Value>
        </Setter>
    </Style>

    <!-- EvernoteTagItem default style -->
    <Style TargetType="{x:Type local:EvernoteTagItem}">
        <Setter Property="FocusVisualStyle" Value="{x:Null}" />
        <Setter Property="MinWidth" Value="50" />
        <Setter Property="Margin" Value="0,0,2,0" />
        <Setter Property="Padding" Value="5,2,0,2" />
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type local:EvernoteTagItem}">
                    <Button x:Name="PART_TagButton" Content="{TemplateBinding Text}" Margin="{TemplateBinding Margin}" Padding="{TemplateBinding Padding}">
                        <Button.Template>
                            <ControlTemplate TargetType="Button">
                                <Border Margin="{TemplateBinding Margin}" Padding="{TemplateBinding Padding}" BorderBrush="Gray" BorderThickness="1" CornerRadius="2" Background="#01FFFFFF">
                                    <Grid >
                                        <Grid.ColumnDefinitions>
                                            <ColumnDefinition Width="*" />
                                            <ColumnDefinition Width="Auto" />
                                        </Grid.ColumnDefinitions>
                                        <ContentPresenter VerticalAlignment="Center" HorizontalAlignment="Left" Margin="0,0,0,2" />
                                        <Button x:Name="PART_DeleteTagButton" Grid.Column="1"  Margin="3,0" VerticalAlignment="Center" HorizontalAlignment="Right" Visibility="Hidden"  >
                                            <Button.Template>
                                                <ControlTemplate>
                                                    <Grid Height="10" Width="10" Background="#01FFFFFF" >
                                                        <Path Stretch="Uniform" ClipToBounds="True" Stroke="{StaticResource HighlightBrush}" StrokeThickness="2" Data="M 85.364473,6.9977109 6.0640998,86.29808 6.5333398,85.76586 M 6.9926698,7.4977169 86.293043,86.79809 85.760823,86.32885"  />
                                                    </Grid>
                                                </ControlTemplate>
                                            </Button.Template>
                                        </Button>
                                    </Grid>
                                </Border>
                                <ControlTemplate.Triggers>
                                    <Trigger Property="IsMouseOver" Value="True">
                                        <Setter Property="Foreground" Value="{StaticResource HighlightBrush}" />
                                        <Setter TargetName="PART_DeleteTagButton" Property="Visibility" Value="Visible" />
                                    </Trigger>
                                </ControlTemplate.Triggers>
                            </ControlTemplate>
                        </Button.Template>
                    </Button>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
        <Style.Triggers>
            <Trigger Property="IsEditing" Value="True">
                <Setter Property="Template">
                    <Setter.Value>
                        <ControlTemplate TargetType="{x:Type local:EvernoteTagItem}">
                            <tkInput:AutoCompleteBox x:Name="PART_InputBox"
                                                             Text="{Binding Text, RelativeSource={RelativeSource TemplatedParent}, Mode=TwoWay}" 
                                                             ItemsSource="{Binding AllTags, RelativeSource={RelativeSource AncestorType={x:Type local:EvernoteTagControl}}}"
                                                             IsTextCompletionEnabled="True"
                                                             />
                        </ControlTemplate>
                    </Setter.Value>
                </Setter>
            </Trigger>
        </Style.Triggers>
    </Style>

</ResourceDictionary>

    private void ListBox_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
    {
        ListBoxItem item = null;
        var d = e.OriginalSource as DependencyObject;
        while (d != null)
        {
            if (d is ListBoxItem)
            {
                item = d as ListBoxItem;
                break;
            }
            d = VisualTreeHelper.GetParent(d);
        }
        if (item != null)
        {
            _popup.IsOpen = false;
            UpdateText(item.Content as string, true);

            // User has selected an item with the mouse... 
            //  ** Add your new code HERE... something like:
            // 
            // TagButton tagButton = new TagButton(_textBox.Text); // _textBox is the TextBox to which the AutoCompleteManager has been applied
            // _autoCompleteTagControl.TagContainer.Add(tagButton); // _autoCompleteTagControl would be the control that we're making... it contains out other controls - I'm assuming we've passed it in or made it available.
        }
    }

    private void TextBox_PreviewKeyDown(object sender, KeyEventArgs e)
    {
        _supressAutoAppend = e.Key == Key.Delete || e.Key == Key.Back;
        if (!_popup.IsOpen)
        {
            return;
        }
        if (e.Key == Key.Enter)
        {
            _popup.IsOpen = false;
            _textBox.SelectAll();

            // User has selected an item by hitting the enter key...
            //  ** Add your new code HERE to create new TagButton, etc.
        }
        // ...
     }

System.Windows.Data Error: 4 : Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType='System.Windows.Controls.ItemsControl', AncestorLevel='1''. BindingExpression:Path=HorizontalContentAlignment; DataItem=null; target element is 'ListBoxItem' (Name=''); target property is 'HorizontalContentAlignment' (type 'HorizontalAlignment')

    void AutoCompleteTextBox_Loaded(object sender, RoutedEventArgs e)
    {
        if (! _isInitialized)
        {
            _acm.AttachTextBox(this);
            _isInitialized = true;
        }
    }