VUE3中的组件传值

一、父传子(props)

在子组件中可以使用defineProps接收父组件向子组件的传值

父组件fatherPage.vue：

<template><div class="father"><button @click="a = a + 1">按钮</button><childPage :a="a" /></div>
</template><script lang="ts" setup>
import { ref } from "vue";
import childPage from "./childPage.vue";
const a = ref<number>(0);
</script>
<style scoped lang="less">
.father {width: 100%;height: 100vh;background-color: rgb(7, 14, 17);display: flex;justify-content: center;align-items: center;button {width: 100px;height: 60px;cursor: pointer;}
}
</style>

子组件childPage.vue：

<template><div class="childPage">{{ a }}</div>
</template>
<script lang="ts" setup>
import { computed, defineProps } from "vue";
// 含默认值
// const porps = defineProps({
//   a: {
//     type: Number,
//     default: 0,
//   },
// });
const props = defineProps({ a: Number });
// 用computed使用props
const a = computed(() => props.a);
</script>
<style scoped lang="less">
.childPage {width: 100px;height: 60px;background-color: rgba(0, 0, 0, 0);display: flex;justify-content: center;align-items: center;color: #ffffff;
}
</style>

效果：

二、子传父(emits)

在子组件中可以使用defineEmits向父组件传递信息。

父组件fatherPage.vue：

<template><div class="father">{{ a }}<childPage @update:a="update" /></div>
</template><script lang="ts" setup>
import { ref } from "vue";
import childPage from "./childPage.vue";
const a = ref<number>(0);
const update = (emitValue: number) => {a.value = emitValue;
};
</script>
<style scoped lang="less">
.father {width: 100%;height: 100vh;background-color: rgb(7, 14, 17);color: #ffffff;display: flex;justify-content: center;align-items: center;button {width: 100px;height: 60px;cursor: pointer;}
}
</style>

子组件childPage.vue：

1.通过点击触发emit传值

<template><div class="childPage"><button @click="updateA">按钮</button></div>
</template><script lang="ts" setup>
import { ref, defineEmits } from "vue";const a = ref<number>(0);
const emit = defineEmits(["update:a"]);
const updateA = () => {a.value++;emit("update:a", a.value);
};
</script><style scoped lang="less">
.childPage {width: 100px;height: 60px;button {width: 100%;height: 100%;cursor: pointer;}
}
</style>

效果：

2.通过watch监听值的变化进行传值：

<template><div class="childPage"><button @click="updateA">按钮</button></div>
</template><script lang="ts" setup>
import { ref, defineEmits, watch } from "vue";const a = ref<number>(0);
const emit = defineEmits(["update:a"]);
const updateA = () => {a.value++;setTimeout(() => {updateA();}, 1000);
};
watch(a, (newValue) => {emit("update:a", newValue);
});
</script><style scoped lang="less">
.childPage {width: 100px;height: 60px;button {width: 100%;height: 100%;cursor: pointer;}
}
</style>

效果：

三、父子组件进行双向绑定(v-model)

在子组件中可以使用defineModel与父组件进行双向绑定。注意：defineModel在vue3.3版本实验性使用，稳定版在vue3.4。

父组件：

<template><div class="father">{{ a }}<childPage v-model="a" /></div>
</template><script lang="ts" setup>
import { ref } from "vue";
import childPage from "./childPage.vue";
const a = ref<number>();
</script>
<style scoped lang="less">
.father {width: 100%;height: 100vh;background-color: rgb(7, 14, 17);color: #ffffff;display: flex;justify-content: center;align-items: center;button {width: 100px;height: 60px;cursor: pointer;}
}
</style>

子组件:

<template><div class="childPage"><button @click="updateA">按钮</button></div>
</template><script lang="ts" setup>
import { defineModel } from "vue";const a = defineModel({type: Number,default: 0,
});const updateA = () => {a.value += 1;
};
</script><style scoped lang="less">
.childPage {width: 100px;height: 60px;button {width: 100%;height: 100%;cursor: pointer;}
}
</style>

效果：

四、使用vuex进行组件通信

使用vuex可以进行组件之间的通信，父子组件与兄弟组件均可

在vuex文件index.ts中：

import { createStore } from "vuex";export default createStore({state: {number: 0,},getters: {},mutations: {changeNumber(state, payload) {state.number = payload;},},actions: {},modules: {},
});

在第一个组件HomeView中：

<template><div class="father">{{ a }}<AboutView /></div>
</template><script lang="ts" setup>
import { computed } from "vue";
import { useStore } from "vuex";
import AboutView from "./AboutView.vue";
const store = useStore();
const a = computed(() => store.state.number);
</script>
<style scoped lang="scss">
.father {width: 100%;height: 100vh;background-color: rgb(7, 14, 17);color: #ffffff;display: flex;justify-content: center;align-items: center;
}
</style>

在第二个组件AboutView中：

<template><div class="childPage"><button @click="updateA">按钮</button></div>
</template><script lang="ts" setup>
import { useStore } from "vuex";const store = useStore();
let a = 0;const updateA = () => {a++;store.commit("changeNumber", a);
};
</script><style scoped lang="scss">
.childPage {width: 100px;height: 60px;button {width: 100%;height: 100%;cursor: pointer;}
}
</style>

效果：

五、使用pinia进行组件通信

pinia有着与vuex类似的功能，同样可以实现组件间的通信。

在store的index.ts文件中：

import { defineStore } from "pinia";
import { ref } from "vue";
export const useCounterStore = defineStore("counter", () => {const count = ref(0);const changeCount = () => {count.value++;};return { count, changeCount };
});

在第一个组件fatherPage中：

<template><div class="father">{{ count }}<childPage /></div>
</template><script lang="ts" setup>
import childPage from "./childPage.vue";
import { useCounterStore } from "../store/index";
import { storeToRefs } from "pinia";
const store = useCounterStore();
const { count } = storeToRefs(store);
</script>
<style scoped lang="less">
.father {width: 100%;height: 100vh;background-color: rgb(7, 14, 17);color: #ffffff;display: flex;justify-content: center;align-items: center;button {width: 100px;height: 60px;cursor: pointer;}
}
</style>

在第二个组件childPage中：

<template><div class="childPage"><button @click="changeCount">按钮</button></div>
</template><script lang="ts" setup>
import { useCounterStore } from "../store/index";
const store = useCounterStore();
const { changeCount } = store;
</script><style scoped lang="less">
.childPage {width: 100px;height: 60px;button {width: 100%;height: 100%;cursor: pointer;}
}
</style>

效果:

六、使用事件总线进行组件通信

我们可以利用第三方库比如说mitt以事件总线的方式实现传值

在mitt的index.ts中：

import mitt from "mitt";
const emitter = mitt();
export default emitter;

在第一个组件fatherPage中：

<template><div class="father">{{ count }}<childPage /></div>
</template><script setup>
import childPage from "./childPage.vue";
import emitter from "@/mitt/index";
import { ref } from "vue";
const count = ref(0);
emitter.on("changeCount", (counter) => {count.value = counter;
});
</script>
<style scoped lang="less">
.father {width: 100%;height: 100vh;background-color: rgb(7, 14, 17);color: #ffffff;display: flex;justify-content: center;align-items: center;button {width: 100px;height: 60px;cursor: pointer;}
}
</style>

在第二个组件childPage中：

<template><div class="childPage"><button @click="changeCount">按钮</button></div>
</template><script setup>
import emitter from "../mitt/index";
let a = 0;
const changeCount = () => {a++;emitter.emit("changeCount", a);
};
</script><style scoped lang="less">
.childPage {width: 100px;height: 60px;button {width: 100%;height: 100%;cursor: pointer;}
}
</style>

效果：