base.EndInvoke("", _args, result) not find

  public string EndUpdateStoreBusinessDateRecord(System.IAsyncResult result)

{
       object[] _args = new object[0];
        string _result = ((string)(base.EndInvoke("UpdateStoreBusinessDateRecord", _args, result)));
        return _result;

}

 

this.storeBizDateRecords = new ObservableCollection<StoreBusinessDateRecord>();

找了半天原来save后没实例化，导致连续累加记录；