vue初學(xué)，選擇器數(shù)據(jù)綁定失敗

<el-menu :default-active="1" class="el-menu-demo" mode="horizontal">
                        <el-menu-item index="1">
                            <a>我發(fā)出的工單</a>
                        </el-menu-item>
                        <el-menu-item index="2">
                            <a>我收到的工單</a>
                        </el-menu-item>
                        <el-menu-item index="3">
                            <a>個人信息</a>
                        </el-menu-item>
                        <el-menu-item index="4">
                            <a>聯(lián)系人</a>
                        </el-menu-item>
                    </el-menu>
                    <div class="line"></div>

                    <span slot="title">狀態(tài)</span>
                    <el-select v-model="state" placeholder="請選擇工單狀態(tài)">
                        <el-option
                                v-for="item in state"
                                :key="item.value"
                                :label="item.label"
                                :value="item.value">
                        </el-option>
                    </el-select>

                    <span slot="title">分類</span>
                    <el-select v-model="sort" placeholder="請選擇工單類別">
                        <el-option
                                v-for="item in sort"
                                :key="item.value"
                                :label="item.label"
                                :value="item.value">
                        </el-option>
                    </el-select>

                    <el-date-picker
                            v-model="value7"
                            type="daterange"
                            align="right"
                            unlink-panels
                            range-separator="至"
                            start-placeholder="開始日期"
                            end-placeholder="結(jié)束日期"
                            :picker-options="pickerOptions2">
                    </el-date-picker>

<script>
    export default {
        data() {
            return {
                state: [{
                    value: '0',
                    label: '全部工單'
                }, {
                    value: '1',
                    label: '未處理'
                }, {
                    value: '2',
                    label: '處理中'
                }, {
                    value: '3',
                    label: '已處理'
                }, {
                    value: '4',
                    label: '已結(jié)單'
                }],
                sort: [{
                    value: '0',
                    label: '全部工單'
                }, {
                    value: '1',
                    label: '文案類'
                }, {
                    value: '2',
                    label: '設(shè)計(jì)類'
                }, {
                    value: '3',
                    label: '開發(fā)類'
                }, {
                    value: '4',
                    label: '采購類'
                }, {
                    value: '4',
                    label: '其他類'
                }],


                //日期選擇器
                pickerOptions2: {
                    shortcuts: [{
                        text: '最近一周',
                        onClick(picker) {
                            const end = new Date();
                            const start = new Date();
                            start.setTime(start.getTime() - 3600 * 1000 * 24 * 7);
                            picker.$emit('pick', [start, end]);
                        }
                    }, {
                        text: '最近一個月',
                        onClick(picker) {
                            const end = new Date();
                            const start = new Date();
                            start.setTime(start.getTime() - 3600 * 1000 * 24 * 30);
                            picker.$emit('pick', [start, end]);
                        }
                    }, {
                        text: '最近三個月',
                        onClick(picker) {
                            const end = new Date();
                            const start = new Date();
                            start.setTime(start.getTime() - 3600 * 1000 * 24 * 90);
                            picker.$emit('pick', [start, end]);
                        }
                    }]
                },
                value6: '',
                value7: '',

                //表格數(shù)據(jù)
                tableData: [{
                    orderNum: '1',
                    orderSort: '開發(fā)',
                    orderTitle: 'BUG測試',
                    orderDescribe:'BUG測試描述',
                    orderState:'處理中',
                    submitTime:'2017.02.28 02:33',
                    endTime:'2017.02.28 02:33 臨近截止'
                }, {
                    orderNum: '1',
                    orderSort: '開發(fā)',
                    orderTitle: 'BUG測試',
                    orderDescribe:'BUG測試描述',
                    orderState:'處理中',
                    submitTime:'2017.02.28 02:33',
                    endTime:'2017.02.28 02:33 臨近截止'
                }, {
                    orderNum: '1',
                    orderSort: '開發(fā)',
                    orderTitle: 'BUG測試',
                    orderDescribe:'BUG測試描述',
                    orderState:'處理中',
                    submitTime:'2017.02.28 02:33',
                    endTime:'2017.02.28 02:33 臨近截止'
                }, {
                    orderNum: '1',
                    orderSort: '開發(fā)',
                    orderTitle: 'BUG測試',
                    orderDescribe:'BUG測試描述',
                    orderState:'處理中',
                    submitTime:'2017.02.28 02:33',
                    endTime:'2017.02.28 02:33 臨近截止'
                }]
            }
        },
        methods: {
            handleSelect(key, keyPath) {
                console.log(key, keyPath);
            },
            handleClick(row) {
                console.log(row);
            }
        }
    }
</script>

請問是什么問題呢？？