ObservableCollection删除问题

做#Weather时，遇到个问题，需要从原来ObservableCollection中删除掉天气缓存

 类结构

public class WeatherInfoModel : INotifyPropertyChanged
    {

        #region private members
        private string _CityField;

        private string _DateField;

        private string _DayField;

        private string _NightField;

        private string _SensibleTemField;

        private string _dConditioinField;

        private string _dTemperatureField;

        private string _dWindPowerField;

        private string _nConditionField;

        private string _nTemperatureField;

        private string _nWindPowerField;

        private string _dImgPath;

        private string _nImgPathField;

        private string _temperatureField;

        #endregion

        #region public Properties
        public string City
        {
            get { return this._CityField; }
            set
            {
                if (this._CityField != value)
                {
                    this._CityField = value;
                    NotifyPropertyChanged("City");
                }
            }
        }

        public string Date
        {
            get { return this._DateField; }
            set
            {
                if (this._DateField != value)
                {
                    this._DateField = value;
                    NotifyPropertyChanged("Date");
                }
            }
        }

        public string Night
        {
            get { return _NightField; }
            set { _NightField = value; NotifyPropertyChanged("Night"); }
        }

        public string SensibleTem
        {
            get { return _SensibleTemField; }
            set { _SensibleTemField = value; NotifyPropertyChanged("SensibleTem"); }
        }

        public string DCondition
        {
            get { return _dConditioinField; }
            set { _dConditioinField = value; NotifyPropertyChanged("DConditioin"); }
        }

        public string Day
        {
            get { return _DayField; }
            set { _DayField = value; NotifyPropertyChanged("Day"); }
        }

        public string DTemperature
        {
            get { return _dTemperatureField; }
            set { _dTemperatureField = value; NotifyPropertyChanged("DTemperature"); }
        }

        public string DWindPower
        {
            get { return _dWindPowerField; }
            set { _dWindPowerField = value; NotifyPropertyChanged("DWindPower"); }
        }

        public string NCondition
        {
            get { return _nConditionField; }
            set { _nConditionField = value; NotifyPropertyChanged("NCondition"); }
        }

        public string NTemperature
        {
            get { return _nTemperatureField; }
            set { _nTemperatureField = value; NotifyPropertyChanged("NTemperature"); }
        }

        public string NWindPower
        {
            get { return _nWindPowerField; }
            set { _nWindPowerField = value; NotifyPropertyChanged("NWindPower"); }
        }

        public string DImgPath
        {
            get { return _dImgPath; }
            set { _dImgPath = value; NotifyPropertyChanged("DImaPath"); }
        }

        public string NImgPath
        {
            get { return _nImgPathField; }
            set { _nImgPathField = value; NotifyPropertyChanged("NImgPath"); }
        }

        public string Temperature
        {
            get { return _temperatureField; }
            set { _temperatureField = value; NotifyPropertyChanged("Temperature"); }
        }


        #endregion

        public event PropertyChangedEventHandler PropertyChanged;

        private void NotifyPropertyChanged(String propertyName)
        {
            PropertyChangedEventHandler handler = PropertyChanged;
            if (null != handler)
            {
                handler(this, new PropertyChangedEventArgs(propertyName));
            }
        }

部分代码

        #region 所有城市天气状况
        private ObservableCollection<Models.WeatherInfoModel> _allCityFiveDaysInfo = new ObservableCollection<Models.WeatherInfoModel>();

        public ObservableCollection<Models.WeatherInfoModel> AllCityFiveDaysInfo
        {
            get { return this._allCityFiveDaysInfo; }
            set { this._allCityFiveDaysInfo = value; }
        }

        #endregion

出错代码

错误现象，第一条数据删除后，第二次循环出错(理论上需要删除5条连续数据)。index变化？？

 //foreach (Models.WeatherInfoModel cache in AllCityFiveDaysInfo)
//{
//    Models.WeatherInfoModel tem = cache;
//    if (tem.City == city)
//        AllCityFiveDaysInfo.Remove(tem);
//}

替换代码：

                for (int i = 0; i < AllCityFiveDaysInfo.Count; i++)
                {
                    if (AllCityFiveDaysInfo[i].City == city)
                    {
                        AllCityFiveDaysInfo.RemoveAt(i);
                        i--;
                    }
                }