<form class="layui-form" lay-filter="searchForm" id="searchForm">
  <div class="layui-col-xs12 layui-col-md3">
     <div class="layui-form-item">
          <div class="layui-inline">
              <label class="layui-form-label">申请人部门</label>
              <div class="layui-input-inline">
                  <ul id="department" data-id="0"></ul>
                  <input name="applyDepartmentId" class="department-input" class="layui-input">
              </div>
          </div>
      </div>
  </div>
</form>

layui.use(['xmSelect'], function () {
	var xmSelect = layui.xmSelect;
	
	function renderDepartment(){
    	xmSelectTreeTest = xmSelect.render({
            el: '#department',
            prop:{name:'name',value:'id'},
            filterable: true,
            data: dep_list_tree,
            tree:{
	            show:true,
	            expandedKeys:[],
	            strict:false,
            },
            on:function (data) {
                var change_type_arr = [];
	            $.each(data.arr, function (index, item) {
	                change_type_arr.push(item.id)
	            });
	            change_type_str = change_type_arr.join(',');
	            form.render('select');
	              searchType(change_type_str)
	            }
          });
	  },
	  // 给input赋值  change_type_str为逗号分隔的字符串
	  function searchType (change_type_str) {
          $('.department-input').val(change_type_str)
      }
})

//回显
//applyShowDataInt为数组格式
xmSelectTreeTest .setValue(applyShowDataInt)

示例
更多请见xmSelect文档接

数据格式