在表达式绑定中使用自定义全局函数 [英] Use custom global function in Expression Binding

问题描述

我知道如何使用表达式绑定.

I see how to use expression binding.

https://sapui5.netweaver.ondemand.com/docs/guide/daf6852a04b44d118963968a1239d2c0.html

我可以使用小范围的函数调用(您可以使用通过全局符号可用的函数，例如 Math.max(...) 或 isNaN(...).)

I can use a small range of function call (You can use functions that are available via global symbols, such as Math.max(...) or isNaN(...).)

我有我的自定义函数 isVisible(sParam) 但我想将 sParam 值直接写入 xml 代码(sParams 永远不会在模型中)，像这样

I have my custom function isVisible(sParam) but I want write the sParam value directly into the xml code (sParams is never in the model), something like this

visible='{=isVisible('01 03 05 06')}'

我的想法是将 isVisible 定义为全局函数，但在调试时程序不要跨越函数代码

My idea is to define isVisible as a global function but in debug the program don't cross the function code

window.isVisible = function (sParam) {
    ...
};

这是文本字符串作为格式化程序中的参数的双重问题功能

推荐答案

只允许特定的全局对象和函数.您可以在 源代码，它应该是您提供的文档链接中的全局符号列表.

There are only specific global objects and functions allowed. You can see a list in the sourcecode which should be the list of global symbols found in the documentation link you provided.

但我只是有一个想法:

成员访问运算符，带有 .操作员

Member access operator with the . operator

您可以创建一个包含函数的实用程序"JSONModel.JSONModel 只接受任何 javascript 对象，并通过绑定路径和数据绑定提供访问.所以你通过 / 访问根对象并在结果对象上调用一个函数:

You can create a 'utility' JSONModel that contains functions. A JSONModel just takes any javascript object and provides access via binding path and databinding to it. So you access the root object via / and call a function on the resulting object:

onInit:function(){
  var utility = {
    isEven: function(x){
      return x % 2 === 0;
    }
  };
  this.getView().setModel(new JSONModel(utility), "utility");
}

<Button text="Hello 1" visible="{:= ${utility>/}.isEven(1) }"/>
<Button text="Hello 2" visible="{:= ${utility>/}.isEven(2) }"/>

您甚至可以通过闭包访问控制器.

You can even access the controller via closure.

当然，您可以在更高级别(在Component 或什至在Core)定义该实用程序模型.您可以拥有多个实用模型，也可以在表达式中混合模型:visible="{= ${utility>/}.doSomething(${bla>/blub}, 42) }(未尝试那个).

Of course you can define that utility model at a higher level (at Component or even at the Core). You can have many utility models and you can mix models in an expression: visible="{= ${utility>/}.doSomething(${bla>/blub}, 42) } (not tried that).

参见 Plunker 的示例

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