Determine topic id to open it in CHM file

I am trying to implemented F1 help for my WinForm application. I have read this thread:

How to create F1 help in windows forms using c#

My question is how do I find the topic id 开发者_如何学Cof my topic in the CHM file? I am using HTML Help Workshop, and I have looked over every HTML file and option and could not find it. Thanks.

Help.ShowHelp(this, "helpfile.chm", HelpNavigator.TopicId, "1234");

You can define topic IDs for your help file as follows:

1. Open your help project (.hhp) in a text editor.

2. Add the [ALIAS] section and define IDs for the topics:

   [ALIAS]
   Foo=MyTopic.htm
   Bar=SomeFolder\AnotherTopic.htm
   

3. Add the [MAP] section and specify the ID values:

   [MAP]
   #define Foo 7
   #define Bar 42
   

4. Re-compile your help file.

More info here: HTML Help - Context Help Ids.