Text crawl in Blend?

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• 2008年3月7日 1:13Vinicius

   
  

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  Can you be more specific or give some example?

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• 2008年3月7日 8:12Modinaddr

   
  

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  Text crawl is what you often see on TV when you watch your favorite news and there is some additional (text) info crawling in the lower third of the screen - typical. What I am working on is very similar. It is an automatized application for TV where you can interactively add your info over SMS to application to be displayed as text crawl. We already have an application for exporting SMSes into XML.
  My problem is I don't even know how to start solving this problem in Blend. I don't know if this should be done in some other environment or what :S . I thought about animate endless text block but I think this would lag application over time.. I am clueless at the moment.
  
  I hope this helps understand my problem a little, and I really need some help.
  
  Thank you
  
  
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• 2008年3月7日 11:03Adrian Vinca MSFT

   
  

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  Hi,
  
  I haven't created any such control but here are some thoughts:
  I think you should create your own control (e.g. TextCrawlControl) - this requires some more advanced knowledge of WPF and you may need to write some code. You could try different ways to implement the control:
  
  1. Have custom code which creates/destroys the items you want to display
  - use a series of TextBlocks you animate right to left
  - dynamically add new TextBlocks, on the right side, in the invisible area of the screen - you could create them every time a new word or sentence needs to enter the screen
  - the control keeps tracks of all the TextBlocks and moves them to the left for every iteration; when a TextBlock reaches the left side, it gets removed from its parent (so that it gets destroyed)
  - the control could expose properties for Speed, Font Size, Font Family, perhaps a queue of items to be displayed
  
  2. Try using VirtualizingStackPanel. Its behavior is very similar to your scenario (it shows a list of items, uses virtualization):
  
  http://msdn2.microsoft.com/en-us/library/system.windows.controls.virtualizingstackpanel.aspx
  
  Hope this helps,
  Adrian
  
  - Adrian Vinca [MSFT]
  Content is provided "AS IS" with no warranties and confers no rights. Opinions are my own and do not represent those of my employer.
  
  

  • 已标记为答案Lori DirksMSFT, 版主2008年11月23日 3:33
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• 2008年3月10日 10:41Modinaddr

   
  

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  Thank you alot Adrian, this is very helpfull. At least i know where to look further :) and i see the problem is not the easy one. Thank you again,
  
  Zoran
  
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• 2008年8月30日 11:07BalaMurugan_Sa

   
  

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  Hi Modinaddr,
  
  I tried a bit to create an user control called 'CrawlTextBox'. 
  
  Please find below the Code... Hope this will help you.
  
  ------------------------------------------------------------------------------------------------------------------------
  XAML Code - UserControl
  ------------------------------------------------------------------------------------------------------------------------
  <UserControl
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
  xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

  mc:Ignorable="d"
  x:Class="TextCrawl.CrawlTextBox"
  x:Name="UserControl"
  d:DesignWidth="640" d:DesignHeight="480">

   <DockPanel LastChildFill="False" Height="32" Width="288" HorizontalAlignment="Left" VerticalAlignment="Top">
  <TextBox Text="TextBox" TextWrapping="Wrap" DockPanel.Dock="Top" Height="32" x:Name="displayTextBox"/>
  </DockPanel>

  </UserControl>
  ------------------------------------------------------------------------------------------------------------------------
  

  --------------------------------------------------------------------------------------
  CodeBehind(C#) of UserControl
  --------------------------------------------------------------------------------------
  using System.Windows.Threading;
  namespace TextCrawl
  {
  public partial class CrawlTextBox
      {

      private DispatcherTimer timer;    
      public CrawlTextBox(){
          this.InitializeComponent();
          Loaded += new RoutedEventHandler(CrawlTextBox_Loaded);
          displayString = "I love WPF. I love SliverLight. I love Coding ";
          displayStringWidth = 15;
          interval = 100;
      }
  

  // This will contain the Displaying text
  private string displayString;
  public string DisplayString{get { return displayString; }set { displayString = value; }}

  // Specify the width of the text that need to shown on the screen
  private int displayStringWidth;public int DisplayStringWidth{get { return displayStringWidth; }set { displayStringWidth = value; }}

  // Specify the speed at which the text should crawl
  private double interval;
  public double Interval{get { return interval; }set { interval = value; }}

  private char tempText;

  private bool enable;

  public bool Enable{get { return enable; }set { enable = value; }}

  void CrawlTextBox_Loaded(object sender, RoutedEventArgs e)
  {

  timer = new DispatcherTimer();
  timer.Interval = TimeSpan.FromMilliseconds(interval);
  timer.Tick += new EventHandler(timer_Tick);
  timer.Start();

  }

  void timer_Tick(object sender, EventArgs e)
  {
  if (!CheckForContent() || enable==false)
      return;

  FormatText();
  displayTextBox.Text = displayString.Substring(0,displayStringWidth);
  }

  private void FormatText()
  {

  tempText = displayString[0];
  // Remove the first character of the string
  displayString = displayString.Remove(0, 1);
  // Add the removed string to the last position of the stirng.
  displayString = displayString.Insert(displayString.Length, tempText.ToString());
  }

  private bool CheckForContent()
  {
  if (displayString.Length < 1)
      return false;
  else
      return true;
  }

  }

  }
  -------------------------------------------------------------------------------------
  Windows.XAML where this 'UserControl' is used.
  -------------------------------------------------------------------------------------
  

  <Window

  x:Name="Window"
  Title="Window1"

  Width="640" Height="480" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" xmlns:TextCrawl="clr-namespace:TextCrawl" Loaded="Window_Loaded">

  <Grid x:Name="LayoutRoot">
      <TextCrawl:CrawlTextBox HorizontalAlignment="Left" VerticalAlignment="Top"     
      x:Name="runText"    Loaded="crawlTextBox_Loaded"/>
  </Grid>

  </Window>
  
  -------------------------------------------------------------------------------------
  
  -------------------------------------------------------------------------------------
  CodeBehind ( where is usercontrol is used)
  -------------------------------------------------------------------------------------
  

  public partial class Window1
  {

      public Window1()
      {
          this.InitializeComponent();

          // Set the 'enable' property to true;
          runText.Enable = true;
      }

  }
  
  -BALA.

  • 已建议为答案BalaMurugan_Sa 2008年8月30日 11:07
  • 已标记为答案Lori DirksMSFT, 版主2008年11月23日 3:33
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• 2008年9月9日 18:54philipsh

   
  

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   Nice job BalaMurugan!  Works nice but the words are a bit jumpy.  I came up with a solution that is very smooth:
  
  http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/7a391faa-8607-4c2b-84d4-4ee3bf55a679
  
       Phil

  • 已编辑philipsh 2008年9月17日 15:13
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