使用Vue.js。
我有两个对象数组，category和categoryPar，category包含名称和父级的名称，categoryPar只包含名称。我想只显示属于选定父级的类别。试着这样做：
<select v-model="editing.categoryPar"">
<option v-for="cat in categoryPar" v-bind:value="cat.name">{{ cat.description }}</option>
</select>
<select v-model="editing.category">
<option v-for="cat in category" v-if="editing.categoryPar == cat.par_name" v-bind:value="cat.name">{{ cat.description }}</option>
</select>
条件已履行但未重新渲染。当我在console vue中使用时。$ forceUpdate（）;然后它工作，直到我改变父选择。
感谢您的帮助。
答案 0 :(得分：2)
您需要先创建所选模型的变量。
目前，您正在为function mathCheck() {
var inputValues1 = document.mathGuesser.mGuesser.value;
var attempts;
for (attempts = 3; attempts >= 0; ) {
if (inputValues1 === 'y = 2x - 3' || inputValues1 === 'y=2x-3') {
document.getElementById("answer").style.color = "Green";
document.getElementById("answer").innerHTML = "<span>" + "Correct" + "</span>";
}
else if (inputValues1 === ' ' || inputValues1 === '') {
document.getElementById("answer").style.color = "Black";
document.getElementById("answer").innerHTML = "<span>" + "Please enter text" + "</span>";
}
else {
document.getElementById("answer").style.color = "Red";
document.getElementById("answer").innerHTML = "<span>" + "Incorrect" + "</span>";
document.getElementById("attempts").innerHTML = attempts;
attempts--;
}
}
document.getElementById("answer").style.color = "Black";
document.getElementById("answer").innerHTML = "No attempts left";
}
提供一个对象，这就是它无效的原因
v-modelnew Vue({
el: '#app',
data () {
return {
selectedCategory: '',
category: [{name: 'A', parent: 'Alpha'}, {name: 'B', parent: 'Bravo'}, {name: 'C', parent: 'Charlie'}],
categoryPar: [{name: 'A'}, {name: 'B'}, {name: 'C'}],
}
},
})