总结：

第一次遍历时

:prop = " '第一层被遍历的数组名.（注意这个点 单引号内全为string）' + index（第一层遍历时定义的index）+ '.(注意这个点 本单引号内为string)当前字段名' "

第二次遍历时

:prop="'第一层被遍历的数组名.（注意这个点 单引号内全为string）' + index（第一层遍历时定义的index）+ '.(注意单引号内的两个点)第二层被遍历的数组名. + 'ind(第二层遍历时定义的index)' + '.(注意点)当前字段名' '"

根据具体使用情景 可以结合行内:rules

<template>
      <el-form
        :model="dialogForm"
        :rules="rules"
        ref="dialogForm"
        label-width="130px"
        label-position="right"
        v-loading="isLoading"
      >
        <div class="add-btn">
          <el-button
            icon="el-icon-plus"
            type="success"
            size="small"
            @click="add"
            >新增按钮</el-button
          >
        </div>
        <el-form-item
          label="版块标题："
          prop="parentTitle"
          :rules="rules.parentTitle"
        >
          <el-input
            size="medium"
            show-word-limit
            type="text"
            v-model="dialogForm.parentTitle"
            maxlength="10"
            placeholder="版块标题"
          ></el-input>
        </el-form-item>
        <el-form-item label="是否自动轮播：" prop="ifRotation" v-if="false">
          <el-radio-group v-model="dialogForm.ifRotation" size="medium">
            <el-radio-button :label="true">是</el-radio-button>
            <el-radio-button :label="false">否</el-radio-button>
          </el-radio-group>
        </el-form-item>
        <div
          class="swipe-ul"
          v-for="(item, index) in dialogForm.contentDTOS"
          :key="index"
        >
          <div class="delete-swipe">
            <el-button
              type="danger"
              icon="el-icon-delete"
              circle
              @click="delSwipe(index)"
            >删除一条</el-button>
          </div>
          <el-form-item
            label="内容主标题："
            :prop="'contentDTOS.' + index + '.componentContentParentTitle'"
            :rules="rules.parentTitle"
          >
            <el-input
              size="medium"
              show-word-limit
              type="text"
              v-model="item.componentContentParentTitle"
              maxlength="20"
              placeholder="请输入内容主标题"
            ></el-input>
          </el-form-item>
          <el-form-item label="内容按钮配置：" prop="buttonDTOS">
            <div class="add-btn">
              <el-button
                icon="el-icon-plus"
                type="success"
                size="small"
                round
                @click="addBtn(index)"
              >
                新增按钮配置</el-button
              >
            </div>
          </el-form-item>
          <div
            v-for="(it, ind) in item.buttonDTOS"
            :key="ind"
            class="btn-config"
          >
            <div class="delete-btn">
              <i
                class="el-icon-circle-close"
                @click="delBtn(index, it, ind)"
              ></i>
            </div>
            <el-form-item
              label="跳转按钮名称："
              :prop="
                'contentDTOS.' + index + '.buttonDTOS.' + ind + '.buttonName'
              "
              :rules="rules.buttonName"
            >
              <el-input
                size="medium"
                show-word-limit
                type="text"
                v-model="it.buttonName"
                maxlength="8"
                placeholder="请输入按钮名称"
              ></el-input>
            </el-form-item>
            <el-form-item
              v-if="Number(it.buttonType) === 3"
              :prop="'contentDTOS.' + index + '.buttonDTOS.' + ind + '.jumpUrl'"
              :rules="rules.jumpUrl"
            >
            </el-form-item>
          </div>
        </div>
      </el-form>
</template>

<script>
    data(){
      return {
          rules: {
             height: [
               { required: true, message: "请输入轮播图高度", trigger: "blur" },
             ],
             jumpUrl: { required: true, message: "请输入跳转路径", trigger: "blur" },
           }, // 校验规则
      }
    }
</script>