ExtJS:如何在函数中更改组件“labelStyle”?

tl/dr公司 : 根本没有 setter labelStyle . 那么我怎样才能改变函数的值呢?

我有一个 afterrender 倾听者和目标设定的颜色 fieldLabel emptyText 而不是 和 字段标签 lableStyle 财产。我试着进去 config 但是找不到。也试着用 Ext.apply()

//Related component `listeners`;
listeners   : {
        afterrender: 'removeLabel',
        focusenter: 'createLabel'
    },

//Related function;
removeLabel: function () {
        let formComponent = ['foocombobox', 'bartextfield', 'zetdatefield'];

        Ext.each(formComponent, function (eachComp) {
            let currentComp = Ext.ComponentQuery.query(eachComp)[0];

            if (currentComp.value === '')) {
                let currentLabel = currentComp.fieldLabel;
                currentComp.setEmptyText(currentLabel);

                //This can not work because of I've reach constructor config. So how can I reach?
                //currentComp.labelStyle  = "color:red;";

                //I tried to manipulate through Ext.apply but did not effect;
                //Ext.apply(currentComp, {labelStyle: "color:red;"});


            }
        });
    },