Я сделал пользовательскую фигуру, которая отображает стрелку, которую вы хотите.
Я использовал некоторый код из класса Rectangle.
Что касается части оформления первого и последнего элементов. Вам понадобится какой-то AttachedBehavior, который настраивает некоторое свойство на основе индекса элемента.
using System;
using System.Windows.Shapes;
using System.Windows;
using System.Windows.Media;
namespace CustomShapes
{
public class SquaredArrow : Shape
{
protected Rect _rect = Rect.Empty;
#region TipOffset
/// <summary>
/// TipOffset Dependency Property
/// </summary>
public static readonly DependencyProperty TipOffsetProperty =
DependencyProperty.Register("TipOffset", typeof(double), typeof(SquaredArrow),
new FrameworkPropertyMetadata((double)10, FrameworkPropertyMetadataOptions.AffectsRender));
/// <summary>
/// Gets or sets the TipOffset property. This dependency property
/// indicates ....
/// </summary>
[System.ComponentModel.Category("SquaredArrow")]
public double TipOffset
{
get { return (double)GetValue(TipOffsetProperty); }
set { SetValue(TipOffsetProperty, value); }
}
#endregion
public SquaredArrow()
{
Rectangle r = new Rectangle();
r.Measure(new Size(100, 100));
r.Arrange(new Rect(0, 0, 100, 100));
}
static SquaredArrow()
{
StretchProperty.OverrideMetadata(typeof(SquaredArrow), new FrameworkPropertyMetadata(Stretch.Fill));
}
protected override Geometry DefiningGeometry
{
get { return CreateShape(); }
}
/// <summary>
/// Return the transformation applied to the geometry before rendering
/// </summary>
public override Transform GeometryTransform
{
get
{
return Transform.Identity;
}
}
/// <summary>
/// This is where the arrow shape is created.
/// </summary>
/// <returns></returns>
private Geometry CreateShape()
{
double width = _rect.Width;
double height = _rect.Height;
double borderOffset = GetStrokeThickness() / 2d;
PathGeometry g = new PathGeometry();
PathFigure figure = new PathFigure();
figure.IsClosed = true;
figure.StartPoint = new Point(borderOffset, borderOffset);
figure.Segments.Add(new LineSegment(new Point(width - TipOffset + borderOffset, borderOffset), true));
figure.Segments.Add(new LineSegment(new Point(width + borderOffset, height / 2d + borderOffset), true));
figure.Segments.Add(new LineSegment(new Point(width + borderOffset - TipOffset, height + borderOffset), true));
figure.Segments.Add(new LineSegment(new Point(borderOffset, height + borderOffset), true));
g.Figures.Add(figure);
return g;
}
/// <summary>
/// Updates DesiredSize of the Rectangle. Called by parent UIElement. This is the first pass of layout.
/// </summary>
/// <param name="constraint">Constraint size is an "upper limit" that Rectangle should not exceed.</param>
/// <returns>Rectangle's desired size.</returns>
protected override Size MeasureOverride(Size constraint)
{
if (Stretch == Stretch.UniformToFill)
{
double width = constraint.Width;
double height = constraint.Height;
if (Double.IsInfinity(width) && Double.IsInfinity(height))
{
return GetNaturalSize();
}
else if (Double.IsInfinity(width) || Double.IsInfinity(height))
{
width = Math.Min(width, height);
}
else
{
width = Math.Max(width, height);
}
return new Size(width, width);
}
return GetNaturalSize();
}
/// <summary>
/// Returns the final size of the shape and cachnes the bounds.
/// </summary>
protected override Size ArrangeOverride(Size finalSize)
{
// Since we do NOT want the RadiusX and RadiusY to change with the rendering transformation, we
// construct the rectangle to fit finalSize with the appropriate Stretch mode. The rendering
// transformation will thus be the identity.
double penThickness = GetStrokeThickness();
double margin = penThickness / 2;
_rect = new Rect(
margin, // X
margin, // Y
Math.Max(0, finalSize.Width - penThickness), // Width
Math.Max(0, finalSize.Height - penThickness)); // Height
switch (Stretch)
{
case Stretch.None:
// A 0 Rect.Width and Rect.Height rectangle
_rect.Width = _rect.Height = 0;
break;
case Stretch.Fill:
// The most common case: a rectangle that fills the box.
// _rect has already been initialized for that.
break;
case Stretch.Uniform:
// The maximal square that fits in the final box
if (_rect.Width > _rect.Height)
{
_rect.Width = _rect.Height;
}
else // _rect.Width <= _rect.Height
{
_rect.Height = _rect.Width;
}
break;
case Stretch.UniformToFill:
// The minimal square that fills the final box
if (_rect.Width < _rect.Height)
{
_rect.Width = _rect.Height;
}
else // _rect.Width >= _rect.Height
{
_rect.Height = _rect.Width;
}
break;
}
return finalSize;
}
/// <summary>
/// Get the natural size of the geometry that defines this shape
/// </summary>
protected Size GetNaturalSize()
{
double strokeThickness = GetStrokeThickness();
return new Size(strokeThickness, strokeThickness);
}
protected double GetStrokeThickness()
{
return this.StrokeThickness;
}
/// <summary>
/// Render callback.
/// </summary>
protected override void OnRender(DrawingContext drawingContext)
{
Pen pen = new Pen(Stroke, GetStrokeThickness());
drawingContext.DrawGeometry(Fill, pen, DefiningGeometry);
}
}
}