将列表框的选定值传递给google-apps-script中的另一个列表框

我认为您只是忘记了为隐藏的小部件设置名称，而只给了一个ID ...，并且您显然知道event参数使用小部件名称来获取其值。:-)

h = app.createHidden("selectedGrade").setId("selectedGrade").setName("selectedGrade");

编辑 ：

糟糕，您是对的，起初我没有注意到。

在玩了一些代码之后，我发现您忘记了使用处理程序的callBackElement的地方，我还添加了另一个隐藏的小部件来保存课程值。这是您的代码的副本，在其中我用textBoxes替换了隐藏的小部件，以查看发生了什么。似乎按预期工作，您可以在一切正常的情况下隐藏文本框，或者再次将其替换为隐藏的小部件。

 function executionStartsHere() { 
   var doc = SpreadsheetApp.getActiveSpreadsheet();
   var app = UiApp.createApplication().setTitle('Course Planner');
   var panel = app.createVerticalPanel();
   panel.setId("main-panel");


   //grades
   panel.add(_getLabel("Grades"));
   uniqueGrades = _findUniqueGrades();
   gradeListBox = _getListBox(app,uniqueGrades,"grade-listbox","grades");
   var gradeHandler = app.createServerHandler('_clickGrade').addCallbackElement(panel);
   gradeListBox.addChangeHandler(gradeHandler);
   panel.add(gradeListBox);

   //courses
   panel.add(_getLabel("Courses"));
   courseListBox = _getListBox(app,{item:'First choose a grade value'},"course-listbox","courses");
   var courseHandler = app.createServerHandler('_clickCourse').addCallbackElement(panel);
   courseListBox.addChangeHandler(courseHandler);
   panel.add(courseListBox);

   //semester
   panel.add(_getLabel("Semester"));
   semesterListBox = _getListBox(app,{item:'First choose a course value'},"semester-listbox","semesters");
   panel.add(semesterListBox);


   var h = app.createTextBox().setName("selectedGrade").setId("selectedGrade");
   var h2 = app.createTextBox().setName("selectedCourse").setId("selectedCourse");
   panel.add(h).add(h2);

   //finally
   app.add(panel);
   doc.show(app);  
 }


 function _clickGrade(eventInfo) {
   var app = UiApp.getActiveApplication();
   // get value of ListBox based on name
   var selectedGrade = eventInfo.parameter.grades;
   Logger.log("In clickGrade, selected:"+selectedGrade);
   //eventInfo.parameter.selectedGrade=selectedGrade;
   app.getElementById("selectedGrade").setValue(selectedGrade);
   Logger.log("eventInfo.parameter.selectedGrade: "+eventInfo.parameter.selectedGrade);
    _displayCourses(selectedGrade);
   return app;
 }

 function _clickCourse(eventInfo) {
   //WE NEED TO SOMEHOW PASS THE SELCTED GRADE IN HERE

   var app    = UiApp.getActiveApplication();
   var grade  = app.getElementById("selectedGrade")
   var grade2 = eventInfo.parameter.selectedGrade;
   var course = eventInfo.parameter.courses;
   app.getElementById("selectedCourse").setValue(course);
    Logger.log("Selected grade, grade2, course: "+grade+" ,"+grade2+" ,"+course);
   _displaySemesters(grade2,course);
   return app;
 }

 function _displayCourses(grade) {
   var app = UiApp.getActiveApplication();
   validCourses = _findValidCourses(grade);
   lb = app.getElementById("course-listbox");
   _populateListBox(lb,validCourses);
 }

 function _displaySemesters(grade,course){
   var app = UiApp.getActiveApplication();
   Logger.log(grade+' '+course)
   validSemesters = _findValidSemesters(grade,course);
   lb = app.getElementById("semester-listbox");
   _populateListBox(lb,validSemesters);
 }


 function _findUniqueGrades(){
   var workBook = _getWorkBook(); 
   var sheet = _getLearningOutcomeSheet(workBook);
   var graderows = getColumnAsArray(sheet, 1); 

   var grades= {}; 
   for(var i=1; i<graderows.length; i++) { //skip the first row (labels)
     if(graderows[i] != "" && graderows[i] != undefined ) {
       grades[graderows[i]]=graderows[i];
     }
   }
   return grades;
 }

 function _findValidCourses(grade) {
  var workBook = _getWorkBook();
  var sheet = _getLearningOutcomeSheet(workBook);
  var graderows = getColumnAsArray(sheet, 1); 
  var courserows = getColumnAsArray(sheet, 3);

  // loop over courserows
  //  if the grade for this courserow matches the grade we are searching for
  //     then store this courserow in an associative array
  validCourses = {};
  for(var i=0; i< courserows.length; i++) {
    if ( graderows[i] == grade ) {
      validCourses[courserows[i]] = courserows[i];
    }
  }
  return validCourses;
 } 

 function _findValidSemesters(grade,course){
  var workBook     = _getWorkBook();
  var sheet        = _getLearningOutcomeSheet(workBook);
  var graderows    = getColumnAsArray(sheet, 1);
  var courserows   = getColumnAsArray(sheet, 3);
  var semesterrows = getColumnAsArray(sheet, 2); 

   validSemesters = {};
   for(var i=0; i< semesterrows.length; i++){
     if ( courserows[i] == course && graderows[i] == grade ){
       validSemesters[semesterrows[i]] = semesterrows[i];
     }
   }
   return validSemesters;
 }

 function _getListBox(app,items,id,label){
   var lb = app.createListBox().setId(id).setName(label);
   lb.setVisibleItemCount(1);
   //add items, if any
   for each ( i in items) {
     lb.addItem(i);
   }
   return lb;
 } 

 function _populateListBox(listBox,items){
   listBox.clear();
   Logger.log("ListBox ID: "+ listBox.getId());
   for each ( i in items) {
     Logger.log("adding item: " + i);
     listBox.addItem(i);
   }
 }

 function _getWorkBook(){
   return SpreadsheetApp.getActiveSpreadsheet()
 }

 function _getLearningOutcomeSheet(workBook){
   return workBook.getSheets()[0];
 }

 function _getLabel(string){
   var app = UiApp.getActiveApplication();
   return app.createLabel(string); 
 }

 function getColumnAsArray(sheet,column) {
  var dataRange = sheet.getRange(1,column,99,1);
  var data = dataRange.getValues()
  //Logger.log("column values: " + data);

  return data;
 }