element表格实现复选框单选

默认表格前面的复选框是可以选择多个，但有的需求是只能选择一个，

可以通过clearSelection和toggleRowSelection去实现，把当前选中的这条selected设置成true。

<div class="same-table">
      <el-table
          :data="tableData"
          class="oneTabel"
          ref="multipleTable"
          border
          fit
          @selection-change="handleSelectionChange"
          @select-all="dialogCheck"
          @select="dialogCheck"
          style="width:100%;">
              <el-table-column type="selection" width="50"></el-table-column>
              <el-table-column type="index" width="60" label="序号"></el-table-column>
              <el-table-column prop="name" label="机构"></el-table-column>
              <el-table-column prop="negativeDec" label="负面清单描述"></el-table-column>
      </el-table>
  </div>

methods: {
       handleSelectionChange(val) {
            console.log(val, 'val')
            this.multipleSelection = val;
        },
        dialogCheck: function(selection, row) {
            console.log(selection, row);
            this.$refs.multipleTable.clearSelection()
            if (selection.length === 0) { 
                return
            }
            if (row) {
                this.selectioned = row
                this.$refs.multipleTable.toggleRowSelection(row, true)
            }
        }
}