Question

我在Controller内部声明了messageBox。我想在onClose方法中使用全局变量。

我试图将其作为参数传递给onClose方法

var that =this;
sap.m.MessageBox.show(
    "Notification " + odata.EvNotificationNo + " has been saved" + attachment_message, 
    {
        icon: sap.m.MessageBox.Icon.SUCCESS,
        title: "Success",
        actions: [
                  "Go to Notification Processing", 
                  sap.m.MessageBox.Action.OK, 
                  sap.m.MessageBox.Action.CANCEL
                 ],
        onClose: function (sAction) {

                 //Here I have use var that

                }
    }
);

我想在onClose方法中使用该变量

Answer 1

onClose方法内没有变量。

好像您在调试器在该方法中暂停时尝试访问该闭合变量。不幸的是，这在基于Chromium的浏览器中无法正常工作。参见Why does Chrome debugger think closed local variable is undefined?

当代码实际运行时，该变量将可用并经过正确评估。

除了上述问题之外，您还可以使用Function.prototype.bind将上下文引用传递给事件处理程序，而不用尝试从方法中访问that。

// var that = this; <-- instead of doing that
MessageBox.show("...", { // MessageBox required from "sap/m/MessageBox"
  // ...,
  onClose: function(sAction) {
    // this.something instead of that.something
  }.bind(this), // pass `this`
  // ...
});

与上述闭包变量的问题相反，当调试器在此处暂停时，方法中始终可以使用上下文（this），您可以从中访问分配给this的任何属性

Answer 2

在show函数外声明变量

var that = this;
var myGlobalVar; //Declare global variable

sap.m.MessageBox.show(
  "Notification " + odata.EvNotificationNo + " has been saved" + attachment_message, {
    icon: sap.m.MessageBox.Icon.SUCCESS,
    title: "Success",
    actions: ["Go to Notification Processing", sap.m.MessageBox.Action.OK, sap.m.MessageBox.Action.CANCEL],
    onClose: function(sAction) {


      myGlobalVar = "foo"; //Set global variable


      if (sAction == "Go to Notification Processing") {

        if (sap.ushell && sap.ushell.Container && sap.ushell.Container.getService) {
          var oCrossAppNavigator = sap.ushell.Container.getService("CrossApplicationNavigation");

          oCrossAppNavigator.toExternal({
            target: {
              semanticObject: "ZUI5_8FNPR_SEMR",
              action: "execute"
            }, //the app you're navigating to 
            params: {
              EvNotificationNo: odata.EvNotificationNo
            }
          });
        } else {
          jQuery.sap.log.info("Cannot Navigate - Application Running Standalone");
        }

      }
    }.bind(that)
  }
);

如何在sap.m.MessageBox的onClose方法内使用全局变量？

2 个答案: