WPF实现简单的跑马灯效果

最近项目上要用到跑马灯的效果，和网上不太相同的是，网上大部分都是连续的，而我们要求的是不连续的。

也就是是，界面上就展示4项（展示项数可变），如果有7项要展示的话，则不断的在4个空格里左跳，当然，衔接上效果不是很好看。

然后，需要支持点击以后进行移除掉不再显示的内容。

效果如下：

思路大致如下：

1、最外层用一个ViewBox，为了可以填充调用此控件的地方，这样可以方便自动拉伸

代码如下:

<Viewbox x:Name="viewbox_main" Height="{Binding Path=ActualHeight}" Width="{Binding Path=ActualWidth}" MouseLeave="grid_main_MouseLeave" MouseMove="grid_main_MouseMove"  HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Stretch="Fill"/>

2、定义三个变量，一个是Count值，是为了设定要展示的UserControl的个数的，例如默认是4个，如效果图，当然，设置成5的话，就是5个了；一个List<Grid>是为了放入展示控件的列表，一个List<UserControl>是用来放所有要用于跑马灯里的控件的。

3、设置一个Canvas，放入到最外层的Viewbox中，用于跑马灯时候用（这也是常用的跑马灯控件Canvas）

//给Canvas设置一些属性
 canvas_board.VerticalAlignment = VerticalAlignment.Stretch;
 canvas_board.HorizontalAlignment = HorizontalAlignment.Stretch;
canvas_board.Width = this.viewbox_main.ActualWidth;
canvas_board.Height = this.viewbox_main.ActualHeight;
canvas_board.ClipToBounds = true;
//用viewbox可以支持拉伸
this.viewbox_main.Child = canvas_board;

4、将要循环的Grid放入到Canvas里，这里的Grid的个数，要比展示的个数大一个，也就是Count+1个值，因为滚动的时候，其实是在最外面有一个的，这样保证了循环的走动。至于两个控件之间的Margin这个就是要设置Grid的了，到时候控件是直接扔进Grid里的

//循环将Grid加入到要展示的列表里
for (int i = 0; i < Uc_Count + 1; i++)
{
 Grid grid = new Grid();
 grid.Width = canvas_board.Width / Uc_Count - 10;
 grid.Height = canvas_board.Height - 10;
 grid.Margin = new Thickness(5);
 this.canvas_board.Children.Add(grid);
 grid.SetValue(Canvas.TopProperty, 0.0);
 grid.SetValue(Canvas.LeftProperty, i * (grid.Width + 10));

 UcListForShow.Add(grid);
}

5、给每个Grid增加一个动画效果，就是向左移动的效果

for (int i = 0; i < UcListForShow.Count; i++)
{
 //设置滚动时候的效果
 DoubleAnimationUsingKeyFrames daukf_uc = new DoubleAnimationUsingKeyFrames();
 LinearDoubleKeyFrame k1_uc = new LinearDoubleKeyFrame(i * (UcListForShow[i].Width + 10), KeyTime.FromTimeSpan(TimeSpan.FromSeconds(2)));
 LinearDoubleKeyFrame k2_uc = new LinearDoubleKeyFrame((i - 1) * (UcListForShow[i].Width + 10), KeyTime.FromTimeSpan(TimeSpan.FromSeconds(2.5)));
 daukf_uc.KeyFrames.Add(k1_uc);
 daukf_uc.KeyFrames.Add(k2_uc);
 storyboard_imgs.Children.Add(daukf_uc);
 Storyboard.SetTarget(daukf_uc, UcListForShow[i]);
 Storyboard.SetTargetProperty(daukf_uc, new PropertyPath("(Canvas.Left)"));
}

6、滚动的时候，要计算UserControl到底是添加到了哪个Grid里面，也就是哪个控件作为了第一位。

我们设置一个索引值scroll_index，默认的时候，scroll_index=0，这是初始的状态，当滚动起来以后，scroll_index = scroll_index + 1 - Uc_Count;

然后，判断，循环的时候，是否是展示列表的末尾了，如果是的话，则要填充的控件是scroll_index %UcListSum.Count（滚动索引，对总数直接取余数），如果不是的话则是scroll_index++ % UcListSum.Count（滚动索引++，对总数直接取余数）

scroll_index = scroll_index + 1 - Uc_Count;

for (int i = 0; i < UcListForShow.Count; i++)
{
 UcListForShow[i].SetValue(Canvas.LeftProperty, i * (UcListForShow[i].Width + 10));
 UserControl uc;
 if (i == UcListForShow.Count - 1)
 {
  uc = UcListSum[scroll_index % UcListSum.Count];
 }
 else
 {
  uc = UcListSum[scroll_index++ % UcListSum.Count];
 }
 if (uc.Parent != null)
 {
  (uc.Parent as Grid).Children.Clear();//将Usercontrol从原来的里面移除掉，要不然会抛错，Usercontrol已属于另一个控件
 }
 UcListForShow[i].Children.Clear();
 UcListForShow[i].Children.Add(uc);
 //将隐藏按钮加入到Grid里
 Button btn = new Button();
 btn.Style = (dictionary["hidenStyle"] as Style);//从样式文件里读取到Button的样式
 btn.Tag = UcListForShow[i].Children;//给Tag赋值，这样方便查找
 btn.Click += Btn_Click;//注册隐藏事件
 UcListForShow[i].Children.Add(btn);
}

代码中，需要注意的是(uc.Parent as Grid).Children.Clear()，如果不移除的话，则会提示，已经属于另一个，所以，要从parent里面移除掉。

7、Button的隐藏事件，当Button点击以后，则要进行隐藏，其实也就是将总数里面，减除掉不再显示的那一项

private void Btn_Click(object sender, RoutedEventArgs e)
{
 if ((sender as Button).Tag != null)
 {
  UcListSum.Remove((((sender as Button).Tag as UIElementCollection)[0] as UserControl));
 }
 if (UcListSum.Count == Uc_Count)//当列表数和要展示的数目相同的时候，就停止掉动画效果
 {
  storyboard_imgs.Completed -= Storyboard_imgs_Completed;
  storyboard_imgs.Stop();
  for (int i = 0; i < Uc_Count; i++)
  {
   UcListForShow[i].Children.Clear();
   if (UcListSum[i].Parent != null)
   {
    (UcListSum[i].Parent as Grid).Children.Clear();
   }
   UcListForShow[i].Children.Add(UcListSum[i]);
  }
  return;
 }
}

所有代码如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace MarqueeUserControl
{
 /// <summary>
 /// MarqueeUC.xaml 的交互逻辑
 /// </summary>
 public partial class MarqueeUC : UserControl
 {
  ResourceDictionary dictionary;
  public MarqueeUC()
  {
   InitializeComponent();
   //读取样式文件
   dictionary = new ResourceDictionary { Source = new Uri("/MarqueeUserControl;component/MarqueeUserControlDictionary.xaml", UriKind.Relative) };
  }
  #region 属性
  private int _uc_Count = 0;
  /// <summary>
  /// 用来展示几个
  /// </summary>
  public int Uc_Count
  {
   get
   {
    return _uc_Count;
   }

   set
   {
    _uc_Count = value;
   }
  }

  private List<Grid> _ucListForShow = new List<Grid>();
  /// <summary>
  /// 用来展示的控件列表
  /// </summary>
  private List<Grid> UcListForShow
  {
   get
   {
    return _ucListForShow;
   }

   set
   {
    _ucListForShow = value;
   }
  }

  private List<UserControl> _ucListSum = new List<UserControl>();
  /// <summary>
  /// 要添加的控件的列表
  /// </summary>
  public List<UserControl> UcListSum
  {
   get
   {
    return _ucListSum;
   }

   set
   {
    _ucListSum = value;
   }
  }

  #endregion
  Canvas canvas_board = new Canvas();
  Storyboard storyboard_imgs = new Storyboard();
  int scroll_index = 0;//滚动索引
  double scroll_width;//滚动宽度

  void GridLayout()
  {
   if (Uc_Count == 0)//如果这个值没有赋值的话，则默认显示四个
   {
    Uc_Count = 4;
   }
   //给Canvas设置一些属性
   canvas_board.VerticalAlignment = VerticalAlignment.Stretch;
   canvas_board.HorizontalAlignment = HorizontalAlignment.Stretch;
   canvas_board.Width = this.viewbox_main.ActualWidth;
   canvas_board.Height = this.viewbox_main.ActualHeight;
   canvas_board.ClipToBounds = true;
   //用viewbox可以支持拉伸
   this.viewbox_main.Child = canvas_board;
   //循环将Grid加入到要展示的列表里
   for (int i = 0; i < Uc_Count + 1; i++)
   {
    Grid grid = new Grid();
    grid.Width = canvas_board.Width / Uc_Count - 10;
    grid.Height = canvas_board.Height - 10;
    grid.Margin = new Thickness(5);
    this.canvas_board.Children.Add(grid);
    grid.SetValue(Canvas.TopProperty, 0.0);
    grid.SetValue(Canvas.LeftProperty, i * (grid.Width + 10));

    UcListForShow.Add(grid);
   }
  }

  void StoryLoad()
  {
   for (int i = 0; i < UcListForShow.Count; i++)
   {//设置滚动时候的效果
    DoubleAnimationUsingKeyFrames daukf_uc = new DoubleAnimationUsingKeyFrames();
    LinearDoubleKeyFrame k1_uc = new LinearDoubleKeyFrame(i * (UcListForShow[i].Width + 10), KeyTime.FromTimeSpan(TimeSpan.FromSeconds(2)));
    LinearDoubleKeyFrame k2_uc = new LinearDoubleKeyFrame((i - 1) * (UcListForShow[i].Width + 10), KeyTime.FromTimeSpan(TimeSpan.FromSeconds(2.5)));
    daukf_uc.KeyFrames.Add(k1_uc);
    daukf_uc.KeyFrames.Add(k2_uc);
    storyboard_imgs.Children.Add(daukf_uc);
    Storyboard.SetTarget(daukf_uc, UcListForShow[i]);
    Storyboard.SetTargetProperty(daukf_uc, new PropertyPath("(Canvas.Left)"));
   }

   storyboard_imgs.FillBehavior = FillBehavior.Stop;
   storyboard_imgs.Completed += Storyboard_imgs_Completed;
   storyboard_imgs.Begin();
  }

  private void Storyboard_imgs_Completed(object sender, EventArgs e)
  {

   scroll_index = scroll_index + 1 - Uc_Count;

   for (int i = 0; i < UcListForShow.Count; i++)
   {
    UcListForShow[i].SetValue(Canvas.LeftProperty, i * (UcListForShow[i].Width + 10));
    UserControl uc;
    if (i == UcListForShow.Count - 1)
    {
     uc = UcListSum[scroll_index % UcListSum.Count];
    }
    else
    {
     uc = UcListSum[scroll_index++ % UcListSum.Count];
    }
    if (uc.Parent != null)
    {
     (uc.Parent as Grid).Children.Clear();//将Usercontrol从原来的里面移除掉，要不然会抛错，Usercontrol已属于另一个控件
    }
    UcListForShow[i].Children.Clear();
    UcListForShow[i].Children.Add(uc);
    //将隐藏按钮加入到Grid里
    Button btn = new Button();
    btn.Style = (dictionary["hidenStyle"] as Style);//从样式文件里读取到Button的样式
    btn.Tag = UcListForShow[i].Children;//给Tag赋值，这样方便查找
    btn.Click += Btn_Click;//注册隐藏事件
    UcListForShow[i].Children.Add(btn);
   }

   storyboard_imgs.Begin();
  }

  private void Btn_Click(object sender, RoutedEventArgs e)
  {
   if ((sender as Button).Tag != null)
   {
    UcListSum.Remove((((sender as Button).Tag as UIElementCollection)[0] as UserControl));
   }
   if (UcListSum.Count == Uc_Count)//当列表数和要展示的数目相同的时候，就停止掉动画效果
   {
    storyboard_imgs.Completed -= Storyboard_imgs_Completed;
    storyboard_imgs.Stop();
    for (int i = 0; i < Uc_Count; i++)
    {
     UcListForShow[i].Children.Clear();
     if (UcListSum[i].Parent != null)
     {
      (UcListSum[i].Parent as Grid).Children.Clear();
     }
     UcListForShow[i].Children.Add(UcListSum[i]);
    }
    return;
   }
  }

  public void StartMar()
  {
   GridLayout();

   scroll_width = this.canvas_board.Width;

   for (int i = 0; i < UcListForShow.Count; i++)
   {
    UserControl uc;
    if (i == UcListForShow.Count - 1)
    {
     uc = UcListSum[scroll_index % UcListSum.Count];
    }
    else
    {
     uc = UcListSum[scroll_index++ % UcListSum.Count];
    }
    if (uc.Parent != null)
    {
     (uc.Parent as Grid).Children.Clear();
    }
    UcListForShow[i].Children.Clear();
    UcListForShow[i].Children.Add(uc);
   }
   StoryLoad();
  }

  private void grid_main_MouseLeave(object sender, MouseEventArgs e)
  {
   if (storyboard_imgs.GetCurrentState() == ClockState.Stopped)//如果是停止的状态，则直接返回，不再起作用
   {
    return;
   }
   if (storyboard_imgs.GetIsPaused() == true)//如果是暂停状态的话，则开始
   {
    storyboard_imgs.Begin();
   }
  }

  private void grid_main_MouseMove(object sender, MouseEventArgs e)
  {
   if (storyboard_imgs.GetIsPaused() == false)
   {
    storyboard_imgs.Pause();
   }
  }
 }
}

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
     xmlns:local="clr-namespace:MarqueeUserControl">
 <Style TargetType="Button" x:Key="hidenStyle">
  <Setter Property="Background" Value="Transparent"/>
  <Setter Property="HorizontalAlignment" Value="Center"/>
  <Setter Property="VerticalAlignment" Value="Center"/>
  <Setter Property="Width" Value="25"/>
  <Setter Property="Height" Value="25"/>
  <Setter Property="BorderBrush" Value="Transparent"/>
  <Setter Property="BorderThickness" Value="0"/>
  <Setter Property="Template"><!--把Image放到Template里作为Content显示，如果是单独给Content设置图片的话，则只有一个按钮显示图片，其他的不显示-->
   <Setter.Value>
    <ControlTemplate TargetType="{x:Type Button}">
     <Border>
      <Image Source="hiden.png"/>
     </Border>
    </ControlTemplate>
   </Setter.Value>
  </Setter>
 </Style>
</ResourceDictionary>

没有解决的问题

想给Button增加鼠标悬停的时候，显示，移除的时候隐藏，但是发现不好使，原因是当MouseOver上去的时候，虽然Visibility的值变了，但是只有到下一次的时候，Button的值才被附上，而此时，已经MouseLeave了，请哪位大神指导一下，看看这个显示和隐藏怎么做。

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