.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
