<el-upload :file-list="fileList" class="upload-demo" action="接口"
multiple v-model="ruleForms.upload" accept=".pdf" :before-upload="changeFiles"
 :on-change="handleChanges">
     <el-button type="primary">選擇文件</el-button>
          <template #tip>
             <div class="el-upload__tip">
                  僅允許上傳一個文件，僅限pdf格式
             </div>
           </template>
</el-upload>

const fileList = ref<UploadUserFile[]>([]);
const handleChange = (file, fileList) => {
    console.log(file, fileList);
    ruleForm.upload = fileList
    //限制文件數量，此處設置限制1條
    if (fileList.length > 1) {
        fileList.splice(0, 1);
    }
};
const changeFile = (file, fileList) => {
    console.log('file', file, fileList);
    if (file.type !== 'application/pdf') {
        ElMessage.error('只能上傳pdf格式的文件');//限制文件類型
        return false;
    } else {
        let param = new FormData();
        param.append('file', file);
        console.log(param);
        axios({
            method: 'POST',
            url: '上傳接口',
            data: param
        }).then((response) => {
            console.log(response); //查看接口返回的數據
        }, function (response) {
            console.log("錯誤信息：" + response)
        });
    }
};