BootStrap select2 动态改变值的方法

var temp=JSON.stringify({ id: "1|所有停车场", name: "所有停车场" });
$("#e_pid").attr("value", tempP);
              $("#e_pid").select2({
                placeholder: "查找停车场名称(多选)",
                language: "zh-CN",
                minimumInputLength: 1,
                allowClear: true,
                multiple: true,
                ajax: {
                  // instead of writing the function to execute the request we use Select2's convenient helper
                  url: "/manage/park/index/json/index",
                  dataType: 'json',
                  data: function (term, page) {
                    return {
                      parkName: term,// search term
                      powerpid: "1"
                    };
                  },
                  results: function (data, page) { // parse the results into the format expected by Select2.
                    // since we are using custom formatting functions we do not need to alter remote JSON data
                    for (var i = 0; i < data.length; i++) {
                      data[i].id = data[i].id+"|"+data[i].name;
                    };
                    data.push({ id: "577cb125f8d2c404572413d1|无", name: "无" });
                    return {
                      results: data
                    };
                  }
                },
                initSelection: function (element, callback) {
//赋初始值
                  // the input tag has a value attribute preloaded that points to a preselected movie's id
                  // this function resolves that id attribute to an object that select2 can render
                  // using its formatResult renderer - that way the movie name is shown preselected
                  var data = [];
                  var value = ""
                  var str = $(element).val().split('^');
                  for (var i = 0; i < str.length; i++) {
                    var temp = JSON.parse(str[i]);
                    value += temp.id + ",";
                    data.push(temp);
                  }
                  ;
                  value = value.substring(0, value.length - 1);
                  $(element).val(value);
                  callback(data);
                },
                formatSelection: function (item) {
                  return item.name;//注意此处的name，要和ajax返回数组的键值一样
                }, // 选择结果中的显示
                formatResult: function (item) {
                  return item.name;//注意此处的name
                },// 搜索列表中的显示
                dropdownCssClass: "bigdrop", // apply css that makes the dropdown taller
                escapeMarkup: function (m) {
                  return m;
                }
              });

$("#e_pid").attr("value", temp);
                          $("#e_pid").trigger('change'); //动态改变值以后必须触发改变时间。否则将不会生效