简单的 WPF 帮助

如果你像我一样，喜欢你的应用程序提供上下文相关的帮助，你可能已经尝试过 ApplicationCommands.Help 命令。为了简化将帮助集成到你的应用程序中，我编写了以下代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Input;
using form = System.Windows.Forms;
using System.Windows.Media;

namespace HelpProvider
{
  /// <summary>
  /// This class provides the ability to easily attach Help functionality
  /// to Framework elements. To use it, you need to
  /// add a reference to the HelpProvider in your XAML. The FilenameProperty
  /// is used to specify the name of the helpfile, and the KeywordProperty specifies
  /// the keyword to be used with the search.
  /// </summary>
  /// <remarks>
  /// The FilenameProperty can be at a higher level of the visual tree than
  /// the KeywordProperty, so you don't need to set the filename each time.
  /// </remarks>
  public static class Help
  {
    /// <summary>
    /// Initialize a new instance of <see cref="Help"/>.
    /// </summary>
    static Help()
    {
      // Rather than having to manually associate the Help command, let's take care
      // of this here.
      CommandManager.RegisterClassCommandBinding(typeof(FrameworkElement),
        new CommandBinding(ApplicationCommands.Help,
          new ExecutedRoutedEventHandler(Executed),
          new CanExecuteRoutedEventHandler(CanExecute)));
    }

    #region Filename

    /// <summary>
    /// Filename Attached Dependency Property
    /// </summary>
    public static readonly DependencyProperty FilenameProperty =
      DependencyProperty.RegisterAttached("Filename", typeof(string), typeof(Help));

    /// <summary>
    /// Gets the Filename property.
    /// </summary>
    public static string GetFilename(DependencyObject d)
    {
      return (string)d.GetValue(FilenameProperty);
    }

    /// <summary>
    /// Sets the Filename property.
    /// </summary>
    public static void SetFilename(DependencyObject d, string value)
    {
      d.SetValue(FilenameProperty, value);
    }

    #endregion
   
    #region Keyword

    /// <summary>
    /// Keyword Attached Dependency Property
    /// </summary>
    public static readonly DependencyProperty KeywordProperty =
      DependencyProperty.RegisterAttached("Keyword", typeof(string), typeof(Help));

    /// <summary>
    /// Gets the Keyword property.
    /// </summary>
    public static string GetKeyword(DependencyObject d)
    {
      return (string)d.GetValue(KeywordProperty);
    }

    /// <summary>
    /// Sets the Keyword property.
    /// </summary>
    public static void SetKeyword(DependencyObject d, string value)
    {
      d.SetValue(KeywordProperty, value);
    }
    #endregion

    #region Helpers
    private static void CanExecute(object sender, CanExecuteRoutedEventArgs args)
    {
      FrameworkElement el = sender as FrameworkElement;
      if (el != null)
      {
        string fileName = FindFilename(el);
        if (!string.IsNullOrEmpty(fileName))
          args.CanExecute = true;
      }
    }

    private static void Executed(object sender, ExecutedRoutedEventArgs args)
    {
      // Call ShowHelp.
      DependencyObject parent = args.OriginalSource as DependencyObject;
      string keyword = GetKeyword(parent);
      if (!string.IsNullOrEmpty(keyword))
      {
        form.Help.ShowHelp(null, FindFilename(parent), keyword);
      }
      else
      {
        form.Help.ShowHelp(null, FindFilename(parent));
      }
    }

    private static string FindFilename(DependencyObject sender)
    {
      if (sender != null)
      {
        string fileName = GetFilename(sender);
        if (!string.IsNullOrEmpty(fileName))
          return fileName;
        return FindFilename(VisualTreeHelper.GetParent(sender));
      }
      return null;
    }
    #endregion

  }
}

使用起来非常简单，在你的 XAML 中设置 Filename，并为你的 FrameworkElement 项目添加任何你需要搜索的关键词。这种方法的优势在于，你可以根据需要将 UI 的不同部分绑定到不同的帮助文件。

<Window
  x:Class="HelpSample.Window1"
  xmlns="<a href="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
	http://schemas.microsoft.com/winfx/2006/xaml/presentation</a>"
  xmlns:x="<a href="http://schemas.microsoft.com/winfx/2006/xaml">
	http://schemas.microsoft.com/winfx/2006/xaml</a>"
  Title="Window1" Height="300" Width="300"
  xmlns:help="clr-namespace:HelpProvider;assembly=HelpProvider"
  help:Help.Filename="MyHelpfile.chm"
  >

希望这能像帮助我一样帮助到你。