DWR中传递外部数据给回调方法(Passing extra data to callbacks)
苏小勇 翻译 http://www.bestunix.net/ 根据官方文档随手翻译的,可以凑合着看. 通常我们都需要传递外部信息给一个回调方法,但是所有的回调方法都只有一个参数(从远程方法返回的值).解决方案是使用j avascript闭包。比如,你需要的回调方法是类似下面的一些东西: 代码 function callbackFunc(dataFromServer, dataFromBrowser) { // do something with dataFromServer and dataFromBrowser …} 那么你可以安排这个方法按照下面的顺序被调用: 代码 var dataFromBrowser = ...;// define an erasure function to store a reference to// dataFromBrowser and to call dataFromServervar callbackProxy = function(dataFromServer) { callbackFunc(dataFromServer, dataFromBrowser);};var callMetaData = { callback:callbackProxy };Remote.method(params, callMetaData); (Call meta-data 的解释在scripting introduction) 换句话说,这个函数,你作为callback传递的实际上并不是callback.它仅仅是一个闭包,实际上是个用来传递附加了客户端数据的数据的代理。 你可以用下面更简洁的方法来写: 代码 var dataFromBrowser = ...;Remote.method(params, { callback:function(dataFromServer) { callbackFunc(dataFromServer, dataFromBrowser); }}); | 代码 | function callbackFunc(dataFromServer, dataFromBrowser) { // do something with dataFromServer and dataFromBrowser …} | 代码 | var dataFromBrowser = ...;// define an erasure function to store a reference to// dataFromBrowser and to call dataFromServervar callbackProxy = function(dataFromServer) { callbackFunc(dataFromServer, dataFromBrowser);};var callMetaData = { callback:callbackProxy };Remote.method(params, callMetaData); | 代码 | var dataFromBrowser = ...;Remote.method(params, { callback:function(dataFromServer) { callbackFunc(dataFromServer, dataFromBrowser); }}); |
---|---|---|---|---|---|---|
代码 | ||||||
function callbackFunc(dataFromServer, dataFromBrowser) { // do something with dataFromServer and dataFromBrowser …} | ||||||
代码 | ||||||
var dataFromBrowser = ...;// define an erasure function to store a reference to// dataFromBrowser and to call dataFromServervar callbackProxy = function(dataFromServer) { callbackFunc(dataFromServer, dataFromBrowser);};var callMetaData = { callback:callbackProxy };Remote.method(params, callMetaData); | ||||||
代码 | ||||||
var dataFromBrowser = ...;Remote.method(params, { callback:function(dataFromServer) { callbackFunc(dataFromServer, dataFromBrowser); }}); |