具有功能的OpenUI5绑定属性，而不是直接访问 [英] OpenUI5 binding property with a function, instead of direct access

问题描述

我想将JSONModel的属性（在这种情况下为flag_baz）绑定到复选框。
事情是json模型看起来像这样。

I would like to bind a property (flag_baz in this case) from a JSONModel to a checkbox. Thing is that the json model looks like this.

{
  foo: "Foo", 
  bar:"Bar", 
  flag_baz : "X"
}

在这种情况下，X表示 true，而空字符串表示 false

in this case X means "true" and an empty string means "false"

我想做的是评估一个将模型绑定到复选框的函数（会将 X /转换为true / false），并在从复选框绑定到模型时评估其他功能（将从true / false转换回 X /\"\"）。

What i would like to do is evaluate a function for binding from model to the checkbox (that would translate "X"/"" to true/false) and evaluate some other function when binding from the checkbox to the model (that would translate from true/false back to "X"/"").

我想要这样的东西：

var checkBox = new Checkbox();
checkBox.bindProperty("checked", "flag_baz", funcFromStringToBool, funcFromBoolToString);

我知道funcFromStringToBool被称为格式化程序。

i know the funcFromStringToBool is called a formatter.

我将如何添加funcFromBoolToString函数？

how would i add the funcFromBoolToString function?

希望这很有道理。

Thx提前。

推荐答案

好，以防万一，我自己找到了答案。

Well in case some cares i've found the answer on my own.

所有绑定都可以使用类似的类型

All bindings can use a type like so

checkBox.bindProperty("checked", { 
      path : "flag_baz", 
      type : new BooleanStringType()
});

BooleanStringType类如下：

the BooleanStringType class would look like this:

sap.ui.model.SimpleType.extend("BooleanStringType", {
    //called when going from model to ui
    formatValue : function(flag_baz){
        return flag_baz === "X";
    },
    //called when going from ui back to the model
    parseValue : function(flag_baz){
        return flag_baz ? "X" : "";
    },
    validateValue : function(flag_baz){
       //some validation if needed
    }
});

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