Meteor：从动态过滤的下拉列表中选择选项

与Meteor一样，当选择另一个下拉列表时动态过滤下拉列表 ：我可以根据select＃1填充select＃2中的项目。

但是我无法以编程方式将选择＃2的特定选项设置为选中 – 至少不是在选择＃1的更改事件之后 – 因为项目尚未填充。

html的：

    {{> hello}}   
 {{#each products}} 
{{name}}
 {{/each}} 
  Select One {{#each categories}} {{name}} {{/each}}   Select One {{#each subCategories}} {{name}} {{/each}}   

.js文件：

 if (Meteor.isClient) { Template.hello.helpers({ products: function() { return Products.find(); }, categories: function() { return Categories.find(); }, subCategories: function() { return Session.get("selectedMainCat") && Categories.findOne({ name: Session.get("selectedMainCat") }).subCategories; } }); Template.hello.events({ "click li": function () { $("#main-cat").val(this.category); Session.set("selectedMainCat", $("#main-cat").val()); // now #sub-cat should be filled because of subCategories helper above $("#sub-cat").val(this.subCategory); // this should select the appropriate subcat, but doesn't. apparently it's slightly too early... }, "change #main-cat": function() { Session.set("selectedMainCat", $("#main-cat").val()); } }); } if (Meteor.isServer) { Meteor.startup(function () { Categories.remove({}); Categories.insert( { name: "MainCategory1", subCategories: [ {name: "SubCategory1.1"}, {name: "SubCategory1.2"} ] } ); Categories.insert( { name: "MainCategory2", subCategories: [ {name: "SubCategory2.1"}, {name: "SubCategory2.2"} ] } ); Products.remove({}); Products.insert({ name: "myProduct1", category: "MainCategory2", subCategory: "SubCategory2.2" }); Products.insert({ name: "myProduct2", category: "MainCategory1", subCategory: "SubCategory1.2" }); }); } 

collection.js：

 Products = new Mongo.Collection('products'); Categories = new Mongo.Collection('categories');