在开发过程中，基本都需要实现帮助功能，而一般帮助功能就是打开一个帮助文档，System.Windows.Forms提供了Help类用于打开帮助文档，挺方便的。
Help类提供的方法如下：
| Name | Description | |
|---|---|---|
 |
ShowHelp(Control, String) | Displays the contents of the Help file at the specified URL. |
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ShowHelp(Control, String, String) | Displays the contents of the Help file found at the specified URL for a specific keyword. |
|
ShowHelp(Control, String, HelpNavigator) | Displays the contents of the Help file found at the specified URL for a specific topic. |
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ShowHelp(Control, String, HelpNavigator, Object) | Displays the contents of the Help file located at the URL supplied by the user. |
|
ShowHelpIndex | Displays the index of the specified Help file. |
|
ShowPopup | Displays a Help pop-up window. |
LZ一般使用ShowHelp(Control, String, HelpNavigator)方法：
System.Windows.Forms.Help.ShowHelp(this, helpFilePath, System.Windows.Forms.HelpNavigator.TableOfContents);
其中，this表示当前的窗体，helpFilePath为帮助文件路径，HelpNavigator指定帮助文件的显示元素。
HelpNavigator：Specifies constants indicating which elements of the Help file to display.
| Member name | Description | |
|---|---|---|
| AssociateIndex | The Help file opens to the index entry for the first letter of a specified topic. | |
| Find | The Help file opens to the search page. | |
| Index | The Help file opens to the index. | |
| KeywordIndex | The Help file opens to the topic with the specified index entry, if one exists; otherwise, the index entry closest to the specified keyword is displayed. | |
| TableOfContents | The Help file opens to the table of contents. | |
| Topic | The Help file opens to a specified topic, if the topic exists. | |
| TopicId | The Help file opens to a topic indicated by a numeric topic identifier. |