elementUI表单验证之动态表单验证

elementUI 中 Form 组件提供了表单验证的功能，只需要通过

rules

属性传入约定的验证规则，并将 Form-Item 的

prop

属性设置为需校验的字段名即可。

（1）常用表单验证

<template>
    <el-form :model="ruleForm" :rules="rules" ref="ruleForm" label-width="100px" class="demo-ruleForm">
          <el-form-item label="活动名称" prop="user">
            <el-input v-model="ruleForm.user"></el-input>
          </el-form-item>
          
          <el-form-item label="活动名称" prop="password">
              <el-input v-model="ruleForm.password"></el-input>
          </el-form-item>
        
          <el-form-item>
            <el-button type="primary" @click="submitForm('ruleForm')">登录</el-button>
            <el-button @click="resetForm('ruleForm')">重置</el-button>
          </el-form-item>
    </el-form>
</template>

<script>
  export default {
    data() {
      return {
        ruleForm: {
          user: '',
          password: '',
        },
        rules: {
          user: [
            { required: true, message: '请输入账号', trigger: 'blur' },
            { min: 3, max: 5, message: '长度在 3 到 5 个字符', trigger: 'blur' }
          ],
          password: [
            { required: true, message: '请输入密码', trigger: 'change' },
            { min: 8, max: 16, message: '长度在 8 到 16 个字符', trigger: 'blur' }
          ],
        }
      };
    },
    methods: {
      submitForm(formName) {
        this.$refs[formName].validate((valid) => {
          if (valid) {
            alert('submit!');
          } else {
            console.log('error submit!!');
            return false;
          }
        });
      },
      resetForm(formName) {
        this.$refs[formName].resetFields();
      }
    }
  }
</script>

（2）自定义验证规则（关键字：validator）

有些需要自定义的校验规则可以作为变量写在data中，然后赋值给validator字段

<template>
    <el-form :model="ruleForm" status-icon :rules="rules" ref="ruleForm" label-width="100px" class="demo-ruleForm">
          <el-form-item label="密码" prop="pass">
            <el-input type="password" v-model="ruleForm.pass" autocomplete="off"></el-input>
          </el-form-item>
          <el-form-item label="确认密码" prop="checkPass">
            <el-input type="password" v-model="ruleForm.checkPass" autocomplete="off"></el-input>
          </el-form-item>
          <el-form-item label="年龄" prop="age">
              <el-input v-model.number="ruleForm.age"></el-input>
          </el-form-item>
            
          <el-form-item>
            <el-button type="primary" @click="submitForm('ruleForm')">提交</el-button>
            <el-button @click="resetForm('ruleForm')">重置</el-button>
          </el-form-item>
    </el-form>
</template>

<script>
export default {
    data() {
      var checkAge = (rule, value, callback) => {
        if (!value) {
          return callback(new Error('年龄不能为空'));
        }
        setTimeout(() => {
          if (!Number.isInteger(value)) {
            callback(new Error('请输入数字值'));
          } else {
            if (value < 18) {
              callback(new Error('必须年满18岁'));
            } else {
              callback();
            }
          }
        }, 1000);
      };
      var validatePass = (rule, value, callback) => {
        if (value === '') {
          callback(new Error('请输入密码'));
        } else {
          if (this.ruleForm.checkPass !== '') {
            this.$refs.ruleForm.validateField('checkPass');
          }
          callback();
        }
      };
      var validatePass2 = (rule, value, callback) => {
        if (value === '') {
          callback(new Error('请再次输入密码'));
        } else if (value !== this.ruleForm.pass) {
          callback(new Error('两次输入密码不一致!'));
        } else {
          callback();
        }
      };
      return {
        ruleForm: {
          pass: '',
          checkPass: '',
          age: ''
        },
        rules: {
          pass: [
            { required: true, validator: validatePass, trigger: 'blur' }
          ],
          checkPass: [
            { required: true, validator: validatePass2, trigger: 'blur' }
          ],
          age: [
            { required: true, validator: checkAge, trigger: 'blur' }
          ]
        }
      };
    },
    methods: {
      submitForm(formName) {
        this.$refs[formName].validate((valid) => {
          if (valid) {
            alert('submit!');
          } else {
            console.log('error submit!!');
            return false;
          }
        });
      },
      resetForm(formName) {
        this.$refs[formName].resetFields();
      }
    }
}
</script>

（3）动态表单验证

实际开发中很常见的需求，此时用rules、prop直接写就对应不上表单mode绑定的对象上的属性，所以需要用循环的方式找到要校验的字段所在数据中的索引，然后再以字符串拼接的方式连上校验字段名称：

<template>
    <div class="container">
        <el-form :model="form" ref="formRef" label-width="100px">
          <el-form-item
            prop="email"
            label="邮箱"
            :rules="[
               { required: true, message: '请输入邮箱地址', trigger: 'blur' },
               { type: 'email', message: '请输入正确的邮箱地址', trigger: ['blur', 'change'] }
            ]">
            <el-input v-model="form.email"></el-input>
          </el-form-item>
          
          <el-form-item class="line-item"
            v-for="(item, index) in form.domains"
            :label="'域名' + index"
            :key="item.key"
            :prop="'domains.' + index + '.value'"
            :rules="{
              required: true, message: '域名不能为空', trigger: 'blur'
            }">
            <el-input v-model="item.value"></el-input>
            <el-button @click.prevent="removeDomain(index)">删除</el-button>
          </el-form-item>
          
          <el-form-item>
            <el-button type="primary" @click="submitForm('formRef')">提交</el-button>
            <el-button @click="addDomain">新增域名</el-button>
            <el-button @click="resetForm('formRef')">重置</el-button>
          </el-form-item>
        </el-form>
    </div>
</template>

<script>
export default {
    data() {
        return {
            form: {
              domains: [{
                value: ''
              }],
              email: ''
            }
        };
    },
    methods: {
        submitForm(formName) {
            this.$refs[formName].validate((valid) => {
              if (valid) {
                alert('submit!');
              } else {
                console.log('error submit!!');
                return false;
              }
            });
        },
        resetForm(formName) {
            this.$refs[formName].resetFields();
        },
        removeDomain(index) {
            this.form.domains.splice(index, 1)
        },
        addDomain() {
            this.form.domains.push({
               value: '',
               key: Date.now()
            });
        }
    }
}
</script>

<style lang="less" scoped>
.container{
    height: 100%;
    background-color: #fff;
    padding: 20px 100px;
    .line-item{
        /deep/.el-form-item__content{
            display: flex;
        }
    }
}    
</style>