Thanks devilfish, i have cloned the source code to my local pc before raising the questions here, and also took a glance on the source,but it is a little bit difficult to get the whole picture of the project if read the source code file by file, i think the faster way is to import the source into the IDE(e.g. vs2010), i searched in the internet,but can not find any useful guide to import the bitshares project into the IDE, maybe my direction is wrong,as i also do not know whether can import the bitshares source into the IDE.