fix: 修复年级筛选班级时未传递参数的问题

src/components/pages/pptEasy/addCourse3.vue

@@ -1415,16 +1415,16 @@ export default {
       this.filteredClassOptions = this.classOptions;
     },
     // 年级选择变化时筛选班级
-    onGradeChange() {
-      if (this.selectedGrade === '') {
+    onGradeChange(selectedGrade) {
+      if (selectedGrade === '') {
         // 选择了全部班级，显示所有班级
         this.filteredClassOptions = this.classOptions;
-      }else if(this.selectedGrade === '1'){
+      }else if(selectedGrade === '1'){
         // 选择了兴趣班级，显示兴趣班级
         this.filteredClassOptions = this.classOptions.filter(item => item.pid === '' || !item.pid);
       }else {
         // 根据选择的年级筛选班级
-        this.filteredClassOptions = this.classOptions.filter(item => item.pid === this.selectedGrade);
+        this.filteredClassOptions = this.classOptions.filter(item => item.pid === selectedGrade);
       }
       // 清空已选择的班级，因为筛选后班级列表可能已经改变
       // this.checkboxList2 = [];