Javascript模拟c#方法重载

每次看John Resig的blog，都会有很大的收获！这次和大家一起分享一个Javascript模拟c#方法重载的例子。

 function loadMethod(object, name, fn){ 
            var old = object[ name ]; 
            if ( old ) 
                object[ name ] = function(){ 
                    if ( fn.length == arguments.length ) 
                        return fn.apply( this, arguments ); 
                    else if ( typeof old == 'function' ) 
                        return old.apply( this, arguments ); 
                }; 
            else 
                object[ name ] = fn; 
        }

下面写一个在用户集合中查找特定用户数量的例子

function UserCount(){ 
            loadMethod(this, "find", function(list){ 
                //查找所有数量
                var i=0;
                return list.length;
            }); 
            loadMethod(this, "find", function(list,pwd){ 
                //查找特定密码的用户数量
                var k=0;
                for(var i=0;i<list.length;i++)
                {
                    if(list[i].pwd==pwd)
                        k++;
                }
                return k;
            }); 
            loadMethod(this, "find", function(list,id, pwd){
                //查找特定密码和id的用户数量 
                var k=0;
                for(var i=0;i<list.length;i++)
                {
                    if(list[i].id==id && list[i].pwd==pwd)
                        k++;
                }
                return k;
            })
        }

//定义集合
        var userlist=new Array();
        userlist.push({id:"holygrace",pwd:"12345"});
        userlist.push({id:"JiangYuYang",pwd:"2233"});
        userlist.push({id:"liyanhong",pwd:"12345"});
        userlist.push({id:"mayun",pwd:"adf"});
        userlist.push({id:"wangzidong",pwd:"3456"});
        
        var count=new UserCount()
        alert("find(userlist)找到\n"+count.find(userlist)+"位");
        alert("find(userlist,\"12345\")找到\n"+count.find(userlist,"12345")+"位");
        alert("find(userlist,\"holygrace\",\"12345\")找到\n"+count.find(userlist,"holygrace","12345")+"位");