身份证为空

src/views/live/liveConfig/idCard.vue

@@ -2,7 +2,7 @@
   <el-form ref="form"  label-width="80px">
     <el-form-item>
       <el-form-item label="上传图片" prop="materialUrl">
-        <img :src="idCardUrl" alt="身份证" style="height: 150px; width: 150px" v-if="idCardUrl.length > 0">
+        <img :src="idCardUrl" alt="身份证" style="height: 150px; width: 150px" v-if="idCardUrl != null">
         <ImageUpload @input="handleUrl" type="image" :num="10" :width="150" :height="150" />
       </el-form-item>
       <el-button type="primary" size="mini" @click="submit">保存</el-button>