项目中的通用查询参数类,它体现了项目架构的大局观

     /// <summary>
    /// 自定义谓词
    /// </summary>
    public class VPredication : IEnumerable<KeyValuePair<string, object>>
    {
        Dictionary<string, object> dicv = null;
        SpacePredication spacePredication = null;
        /// <summary>
        /// 区间谓词
        /// </summary>
        public SpacePredication SpacePredication { get { return this.spacePredication; } }

        /// <summary>
        /// 自定义区间 构造函数
        /// </summary>
        public VPredication()
        {
            spacePredication = new SpacePredication();
            dicv = new Dictionary<string, object>();
        }

        /// <summary>
        /// 验证键是否存在值
        /// </summary>
        /// <param name="index">键</param>
        /// <returns>bool</returns>
        public bool ContainsKey(string index)
        {
            return this.dicv.ContainsKey(index);
        }

        /// <summary>
        /// 索引器
        /// </summary>
        /// <param name="index">索引值</param>
        /// <returns>值</returns>
        public object this[string index]
        {
            get
            {
                if (dicv.ContainsKey(index))
                    return dicv[index];
                else
                    return null;
            }
        }


        /// <summary>
        /// 增加新项
        /// </summary>
        /// <param name="key">列枚举[只能接受非FLAG得单个枚举]</param>
        /// <param name="extremumPair"></param>
        public void AddItem(string key, object value)
        {
            this.dicv.Add(key, value);
        }
        /// <summary>
        /// 移除制定 列枚举 的项
        /// </summary>
        /// <param name="key">列枚举[只能接受非FLAG得单个枚举]</param>
        public void RemoveItem(string key)
        {
            this.dicv.Remove(key);
        }

        #region IEnumerable<KeyValuePair<string,object>> 成员

        public IEnumerator<KeyValuePair<string, object>> GetEnumerator()
        {
            return this.dicv.GetEnumerator();
        }

        #endregion

        #region IEnumerable 成员

        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
        {
            return this.dicv.GetEnumerator();
        }

        #endregion
    }
    /// <summary>
    /// 区间谓词
    /// </summary>
    public class SpacePredication : IEnumerable<KeyValuePair<string, ExtremumPair>>
    {
        Dictionary<string, ExtremumPair> dic = null;
        /// <summary>
        /// 区间谓词 构造函数
        /// </summary>
        public SpacePredication()
        {
            dic = new Dictionary<string, ExtremumPair>();

        }

        /// <summary>
        /// 索引器
        /// </summary>
        /// <param name="index">索引值</param>
        /// <returns>区间极值值对</returns>
        public ExtremumPair this[string index]
        {
            get { return dic[index]; }
        }

        /// <summary>
        /// 验证键是否存在值
        /// </summary>
        /// <param name="index">键</param>
        /// <returns>bool</returns>
        public bool ContainsKey(string index)
        {
            return this.dic.ContainsKey(index);
        }



        /// <summary>
        /// 增加新项
        /// </summary>
        /// <param name="_enum">列枚举[只能接受非FLAG得单个枚举]</param>
        /// <param name="extremumPair"></param>
        public void AddItem(string key, ExtremumPair extremumPair)
        {
            this.dic.Add(key, extremumPair);
        }
        /// <summary>
        /// 移除制定 列枚举 的项
        /// </summary>
        /// <param name="key">列枚举[只能接受非FLAG得单个枚举]</param>
        public void RemoveItem(string key)
        {
            this.dic.Remove(key);
        }

        #region IEnumerable<KeyValuePair<string,ExtremumPair>> 成员

        public IEnumerator<KeyValuePair<string, ExtremumPair>> GetEnumerator()
        {
            return this.dic.GetEnumerator();
        }

        #endregion

        #region IEnumerable 成员

        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
        {
            return this.dic.GetEnumerator();
        }

        #endregion
    }

    /// <summary>
    /// 区间极值值对
    /// </summary>
    public class ExtremumPair
    {
        object leftValue, rightValue;
        /// <summary>
        /// 左极值
        /// </summary>
        public object LeftValue { get { return leftValue; } }
        /// <summary>
        /// 右极值
        /// </summary>
        public object RightValue { get { return rightValue; } }
        /// <summary>
        /// 区间极值值对 构造函数
        /// </summary>
        /// <param name="leftValue">左极值</param>
        /// <param name="rightValue">右极值</param>
        public ExtremumPair(object leftValue, object rightValue)
        {
            this.leftValue = leftValue;
            this.rightValue = rightValue;
        }
    }

    /// <summary>
    /// 通用分页参数
    /// </summary>
    public class PagingParam
    {
        int pageSize = 10;
        int pageIndex = 1;
        int pageTotal = -1;
        /// <summary>
        /// 页面大小
        /// </summary>
        public int PageSize { get { return pageSize; } }
        /// <summary>
        /// 页码
        /// </summary>
        public int PageIndex { get { return pageIndex; } }

        public int PageTotal { get { return pageTotal; } }
        /// 构造函数
        /// </summary>
        public PagingParam()
        {
        }
        /// <summary>
        /// 通用分页参数结构 构造函数
        /// </summary>
        /// <param name="pageIndex">页码</param>
        /// <param name="pageSize">页面大小</param>
        public PagingParam(int pageIndex, int pageSize)
        {
            this.pageIndex = pageIndex;
            this.pageSize = pageSize;
            this.pageTotal = PageSize;
        }

        public PagingParam(int pageIndex, int pageSize, int pageTotal)
        {
            this.pageIndex = pageIndex;
            this.pageSize = pageSize;
            this.pageTotal = pageTotal;
        }

    }