1.<el-dialog>下面的<el-form>添加rules验证后再次点开，验证已经启用

需要在el-dialog关闭的时候重置下窗体，重点代码为
@close="$reset('noticeInfoForm')"

例子如下：

<el-dialog
      :close-on-click-modal="false"
      width="70%"
      :before-close="dialogClose"
      :title="title"
      :visible.sync="noticeDialogVisible"
      @close="$reset('noticeInfoForm')"
    >

 <el-form  ref="noticeInfoForm" :model="notice"  label-width="100px" :rules="rules">
        <el-form-item label="xxx" prop="title">
        </el-form-item>
        <el-form-item size="small" label="xxx" prop="content">
        </el-form-item>
 </el-form>
</el-dialog>


//rules定义在data()中

 rules: {
          title: [
            { required: true, message: '请输入标题', trigger: 'blur' },
          ],
          content: [
            { required: false, message: '请输入内容', trigger: 'blur' },
            ],
        },