我弄出来了啊

System.Diagnostics.Process proc = new System.Diagnostics.Process();
proc.StartInfo.FileName = @"帮助文档.chm";
proc.StartInfo.Verb = "Open";
proc.StartInfo.CreateNoWindow = true;
proc.StartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Normal;
proc.Start();

高手指导,嘿嘿

我看别人还有这样的！

string help = "xxx.chm";
Help.ShowHelp(this,help);