.NET 一些常用的类型转换扩展

记录下在开发中经常用到的类型转换

        #region 转换为string
        /// <summary>
        /// 将object转换为string，若转换失败，则返回""。不抛出异常。  
        /// </summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        public static string ParseToString(this object obj)
        {
            return Convert.ToString(obj) ?? string.Empty;
        }
        #endregion

        #region 转换为long
        /// <summary>
        /// 将object转换为long，若转换失败，则返回0。不抛出异常。  
        /// </summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        public static long ParseToLong(this object obj)
        {
            if (obj == null)
            {
                return 0;
            }
            else
            {
                bool boolean = long.TryParse(obj.ToString() ?? string.Empty, out long result);
                return result;
            }
        }

        /// <summary>
        /// 将object转换为long，若转换失败，则返回指定值。不抛出异常。  
        /// </summary>
        /// <param name="obj"></param>
        /// <param name="defaultValue"></param>
        /// <returns></returns>
        public static long ParseToLong(this object obj, long defaultValue)
        {
            if (obj == null)
            {
                return defaultValue;
            }
            else
            {
                bool boolean = long.TryParse(obj.ToString() ?? string.Empty, out long result);
                if (boolean)
                    return result;
                else
                    return defaultValue;
            }
        }

        #endregion

        #region 转换为int
        /// <summary>
        /// 将object转换为int，若转换失败，则返回0。不抛出异常。  
        /// </summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        public static int ParseToInt(this object obj)
        {
            if (obj == null)
            {
                return 0;
            }
            else
            {
                bool boolean = int.TryParse(obj.ToString() ?? string.Empty, out int result);
                return result;
            }
        }

        /// <summary>
        /// 将object转换为int，若转换失败，则返回指定值。不抛出异常。 
        /// null返回默认值
        /// </summary>
        /// <param name="obj"></param>
        /// <param name="defaultValue"></param>
        /// <returns></returns>
        public static int ParseToInt(this object obj, int defaultValue)
        {
            if (obj == null)
            {
                return defaultValue;
            }
            else
            {
                bool boolean = int.TryParse(obj.ToString() ?? string.Empty, out int result);
                if (boolean)
                    return result;
                else
                    return defaultValue;
            }
        }

        #endregion

        #region 转换为double

        /// <summary>
        /// 将object转换为double，若转换失败，则返回0。不抛出异常。  
        /// </summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        public static double ParseToDouble(this object obj)
        {

            if (obj == null)
            {
                return 0;
            }
            else
            {
                bool boolean = double.TryParse(obj.ToString() ?? string.Empty, out double result);
                return result;
            }
        }

        /// <summary>
        /// 将object转换为double，若转换失败，则返回指定值。不抛出异常。  
        /// </summary>
        /// <param name="obj"></param>
        /// <param name="defaultValue"></param>
        /// <returns></returns>
        public static double ParseToDouble(this object obj, double defaultValue)
        {
            if (obj == null)
            {
                return defaultValue;
            }
            else
            {
                bool boolean = double.TryParse(obj.ToString() ?? string.Empty, out double result);
                if (boolean)
                    return result;
                else
                    return defaultValue;
            }
        }

        #endregion

        #region 转换为demical
        /// <summary>
        /// 将object转换为demical，若转换失败，则返回0。不抛出异常。  
        /// </summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        public static decimal ParseToDecimal(this object obj)
        {
            if (obj == null)
            {
                return 0;
            }
            else
            {
                bool boolean = decimal.TryParse(obj.ToString() ?? string.Empty, out decimal result);
                return result;
            }
        }

        /// <summary>
        /// 将object转换为demical，若转换失败，则返回指定值。不抛出异常。  
        /// </summary>
        /// <param name="obj"></param>
        /// <param name="defaultValue"></param>
        /// <returns></returns>
        public static decimal ParseToDecimal(this object obj, decimal defaultValue)
        {
            if (obj == null)
            {
                return defaultValue;
            }
            else
            {
                bool boolean = decimal.TryParse(obj.ToString() ?? string.Empty, out decimal result);
                if (boolean)
                    return result;
                else
                    return defaultValue;
            }
        }
        #endregion

        #region 转化为bool
        /// <summary>
        /// 将object转换为bool，若转换失败，则返回false。不抛出异常。  
        /// </summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        public static bool ParseToBool(this object obj)
        {
            if (obj == null)
            {
                return false;
            }
            else
            {
                bool boolean = bool.TryParse(obj.ToString() ?? string.Empty, out bool result);
                return result;
            }
        }

        /// <summary>
        /// 将object转换为bool，若转换失败，则返回指定值。不抛出异常。  
        /// </summary>
        /// <param name="obj"></param>
        /// <param name="defaultValue"></param>
        /// <returns></returns>
        public static bool ParseToBool(this object obj, bool defaultValue)
        {
            if (obj == null)
            {
                return defaultValue;
            }
            else
            {
                bool boolean = bool.TryParse(obj.ToString() ?? string.Empty, out bool result);
                if (boolean)
                    return result;
                else
                    return defaultValue;
            }
        }

        #endregion

        #region 时间与时间戳转换
        /// <summary>
        /// 时间转换为毫秒时间戳
        /// </summary>
        /// <param name="nowTime"></param>
        /// <returns>时间戳(毫秒)</returns>
        public static long ParseToUnixTime(this DateTime nowTime)
        {
            var startTime = new DateTime(1970, 1, 1, 0, 0, 0, 0);
            return (long)Math.Round((nowTime - startTime).TotalMilliseconds, MidpointRounding.AwayFromZero);
        }

        #endregion

        #region 删除最后一个字符之后的字符
        /// <summary>
        /// 删除最后结尾的一个逗号
        /// </summary>
        public static string DelLastComma(string str)
        {
            return str.Substring(0, str.LastIndexOf(","));
        }
        /// <summary>
        /// 删除最后结尾的指定字符后的字符
        /// </summary>
        public static string DelLastChar(string str, string strchar)
        {
            return str.Substring(0, str.LastIndexOf(strchar));
        }
        /// <summary>
        /// 删除最后结尾的长度
        /// </summary>
        /// <param name="str"></param>
        /// <param name="Length"></param>
        /// <returns></returns>
        public static string DelLastLength(string str, int Length)
        {
            if (string.IsNullOrEmpty(str))
                return "";
            str = str.Substring(0, str.Length - Length);
            return str;
        }
        #endregion

        #region 强制转换类型
        /// <summary>
        /// 强制转换类型
        /// </summary>
        /// <typeparam name="TResult"></typeparam>
        /// <param name="source"></param>
        /// <returns></returns>
        public static IEnumerable<TResult> CastSuper<TResult>(this IEnumerable source)
        {
            return from object item in source select (TResult)Convert.ChangeType(item, typeof(TResult));
        }

        #endregion

        #region List转DataTable
        /// <summary>
        /// List转DataTable
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="list"></param>
        /// <returns></returns>
        public static DataTable ListToDataTable<T>(IEnumerable<T> list)
        {
            //创建属性的集合 
            List<PropertyInfo> pList = new List<PropertyInfo>();
            //获得反射的入口 
            Type type = typeof(T);
            DataTable dt = new DataTable();
            //把所有的public属性加入到集合 并添加DataTable的列 
            Array.ForEach<PropertyInfo>(type.GetProperties(), p =>
            {
                pList.Add(p);
                var theType = p.PropertyType;
                //处理可空类型
                if (theType.IsGenericType && theType.GetGenericTypeDefinition().Equals(typeof(Nullable<>)))
                {
                    dt.Columns.Add(p.Name, Nullable.GetUnderlyingType(theType));
                }
                else
                {
                    dt.Columns.Add(p.Name, theType);
                }
            });
            foreach (var item in list)
            {
                //创建一个DataRow实例 
                DataRow row = dt.NewRow();
                //给row 赋值 
                pList.ForEach(p =>
                {
                    var v = p.GetValue(item, null);
                    row[p.Name] = v == null ? DBNull.Value : v;
                });
                //加入到DataTable 
                dt.Rows.Add(row);
            }
            return dt;
        }


        /// <summary>
        /// List转DataTable
        /// </summary>
        /// <param name="list"></param>
        /// <returns></returns>
        public static DataTable ListToDataTableNew(List<dynamic> list)
        {
            Dictionary<string, string> dic = new Dictionary<string, string>();
            DataTable dt = new DataTable();
            if (list != null && list.Count > 0)
            {
                foreach (var item in list[0])
                {
                    string text = item.ToString();
                    string key = text.Substring(1, text.IndexOf(',') - 1);
                    string value = text.Substring(text.IndexOf(',') + 1, text.Length - text.IndexOf(',') - 2);
                    dt.Columns.Add(key);
                }
            }
            foreach (var vlist in list)
            {
                DataRow row = dt.NewRow();
                foreach (var item in vlist)
                {
                    string text = item.ToString();
                    string key = text.Substring(1, text.IndexOf(',') - 1);
                    string value = text.Substring(text.IndexOf(',') + 1, text.Length - text.IndexOf(',') - 2);
                    //创建一个DataRow实例 
                    row[key] = value;
                }
                //加入到DataTable 
                dt.Rows.Add(row);
            }
            return dt;
        }
        #endregion