Sapui5 如何访问fireBuy（）方法中随事件对象一起传递的对象？

代码如上所示。我想在change回调函数中获得someData属性，我如何才能实现这一点？我尝试了oEvent.someData，但得到了未定义的警报。代码来自nabisoft网站，但没有解释如何访问fireBuy方法传递的对象。

oEvent.GetParameterSomeData解决了这个问题

<script>
        sap.ui.core.Control.extend("com.controls.MyButton", {
            metadata: {
                aggregations: {
                    buyButton : { type: "sap.ui.commons.Button", multiple: false}
                },
                events: {
                    buy: {enablePreventDefault: true}
                }
            },
            init: function() {
                var oControl = this;
                 //create a button to allow used buying that book
                var oBuyBtn = new sap.ui.commons.Button({
                    text: "Click Me",
                    press: function (oEvent) {
                        oControl.fireBuy({
                            someData : "some data I want to pass along with the event object"
                        });
                    }
                });
                this.setAggregation("buyButton", oBuyBtn);

            },
            renderer: {
                render: function(oRm, oControl) {
                    oRm.renderControl(oControl.getAggregation("buyButton"));
                }
            }
        });

        var oButton = new com.controls.MyButton({
            buy: function(oEvent) {
                alert(oEvent.someData);
            }
        });
        oButton.placeAt("content");
    </script>

        var oButton = new com.controls.MyButton({
            buy: function(oEvent) {
                alert(oEvent.getParameter("someData"));
            }
        });