如何将一个javascript变量传递到groovy块 [英] How to pass a javascript variable into a groovy block

问题描述

我需要在我的javascript函数中管理一个groovy列表对象。
我有一个常用的JavaScript功能块。
我试过这个：

  var obj = $ {mediaObjectInstanceList as grails.converters.JSON} [index]; 
  

与此：

  var obj = $ {mediaObjectInstanceList.get（index）}; 
  

但两者都是错误的。在第二部分中，我将指定indexint javascript变量出于groovy块。

解决方案

正如Injecteer回答的那样，不能这样做。主要是因为：

• groovy块在服务器端执行：它们无法识别JavaScript中只有浏览器才知道的变量。 li>
  
• javascript执行客户端，即。浏览器不知道变量 mediaObjectInstanceList （仅由您的grails应用程序知道）。
  

两个（主要）解决方案：

• 当页面生成时，您不知道您的索引（no params in你需要）=>你必须生成整个数组服务器端（groovy），以便在客户端（javascript）可用。

  
  $ b $ var mediaObjectInstanceListInJS = new Array（$ { mediaObjectInstanceList.collect {it as JSON} .join（'，'）}）;
  var someVal = mediaObjectInstanceListInJS [index];




• 您已经拥有索引服务器端（在您的请求中带有参数）=> groovy仅阻止您选择的对象：

  
  
  

  var someVal = $ {mediaObjectInstanceListInJS [params.index] as JSON};

I need to manage a groovy list object in my javascript function. I have a groovy block into a javascript function. I tried with this:

var obj = ${mediaObjectInstanceList as grails.converters.JSON}[index];

and this:

var obj = ${mediaObjectInstanceList.get(index)};

but both are wrong. In the second I would specify the "index" int javascript variable out of the groovy block.

解决方案

As answered by injecteer, you can't do that. Mostly because :

• groovy blocks are executed server side : they can't be aware of variables in javascript only know by the browsers.
• javascript is executed client side, ie. browsers don't know the variable mediaObjectInstanceList (only known by your grails application).

Two (main) solutions :

• you don't know your index when the page is generated (no params in your request) => You have to generate the whole array server side (groovy) to be available at client side (javascript).

  var mediaObjectInstanceListInJS = new Array( ${mediaObjectInstanceList.collect { it as JSON}.join(',')} ); var someVal = mediaObjectInstanceListInJS[index];

• you already have the index server side (with params in your request) => you can get in groovy block only your selected object :

  var someVal = ${mediaObjectInstanceListInJS[params.index] as JSON} ;

这篇关于如何将一个javascript变量传递到groovy块的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！