http://q.cnblogs.com/q/51693/
这种的话，一般公用就好了。，如下的写法：
[HttpGet]
public ActionResult UserManage(int userId=0)
{
if (userId==0)
{
return ActionResult(new UserInfo());
}
else {
ViewBag.IsEdit = true;
return ActionResult(GetUserInfo(userId));
}
}
[HttpPost]
public ActionResult UserManage(UserInfo model,bool isEdit)
{
if (isEdit)
{
do something...
}else
{
do something...
}
}