一个图表的例子

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

namespace SilverlightExcel
{
public partial class Page : UserControl
{
private const int START_YEAR = 2003;
private const int END_YEAR = 2007;

private Polygon _selectedPolygon;

private Dictionary<int, int> _yearProfits;

public Page()
{
InitializeComponent();

FillYearProfits();
RegisterBarEvents();
}

private void FillYearProfits()
{
_yearProfits = new Dictionary<int, int>();

    _yearProfits.Add(2003, 66000);
    _yearProfits.Add(2004, 79000);
    _yearProfits.Add(2005, 85000);
    _yearProfits.Add(2006, 116000);
    _yearProfits.Add(2007, 210000);
}

private int GetProfitForBar(string barName)
{
int year;
int profit;

    try
    {
        year = Int32.Parse(barName.Substring(3));

        profit = _yearProfits[year];
    }
    catch
    {
        profit = 0;
    }

return profit;
}

private void RegisterBarEvents()
{
    for (int year = START_YEAR; year <= END_YEAR; year++)
    {
        Polygon oneBar = this.FindName("bar" + year.ToString()) as Polygon;

        if (oneBar != null)
        {
            oneBar.MouseEnter += new MouseEventHandler(oneBar_MouseEnter);
            oneBar.MouseLeave += new MouseEventHandler(oneBar_MouseLeave);
        }
    }
}

void oneBar_MouseEnter(object sender, MouseEventArgs e)
{
Polygon currentBar = sender as Polygon;

    if (currentBar != null)
    {
        currentBar.StrokeThickness = 1;
        currentBar.Stroke = new SolidColorBrush(Colors.Black);

_selectedPolygon = currentBar;

        ValueTextBlock.Text = string.Format("${0:#,000.00}",
                              GetProfitForBar(currentBar.Name));
        ValueTextBlock.Measure(new Size(double.PositiveInfinity,
                                        double.PositiveInfinity));

Rect polygonBounds = GetPolygonBounds(currentBar.Points);

        ValueTextBlock.Visibility = Visibility.Visible;

        Canvas.SetLeft(ValueTextBlock,
            polygonBounds.X + (polygonBounds.Width / 2) -
            (ValueTextBlock.ActualWidth / 2));

Canvas.SetTop(ValueTextBlock, polygonBounds.Y - 20);
}
}

void oneBar_MouseLeave(object sender, MouseEventArgs e)
{
    if (_selectedPolygon != null)
    {
        _selectedPolygon.StrokeThickness = 0;
        _selectedPolygon.Stroke = null;

ValueTextBlock.Visibility = Visibility.Collapsed;

_selectedPolygon = null;
}
}

private Rect GetPolygonBounds(PointCollection points)
{
double minX, minY;
double maxX, maxY;

if (points == null || points.Count == 0) return Rect.Empty;

    maxX = 0;
    maxY = 0;
    minX = double.MaxValue;
    minY = double.MaxValue;

    foreach (Point onePoint in points)
    {
        if (onePoint.X < minX)
            minX = onePoint.X;

if (onePoint.Y < minY)
minY = onePoint.Y;

if (onePoint.X > maxX)
maxX = onePoint.X;

        if (onePoint.Y > maxY)
            maxY = onePoint.Y;
    }

return new Rect(minX, minY, maxX - minX, maxY - minY);
}
}
}

关于作者：王昕（QQ:475660）在广州工作生活30余年。十多年开发经验，在Java、即时通讯、NoSQL、BPM、大数据等领域较有经验。
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