C#实现在购物车系统中生成不重复订单号的方法

#region 生成单据号/// <summary>/// 生成单据号/// </summary>/// <param name="pFromType"></param>/// <returns></returns>public static string GetFormCode(FormType pFromType){ string formcode = ""; switch(pFromType) { case FormType.CaiGou: {  formcode = "CG";  break; } case FormType.ChaiXie: {  formcode = "CX";  break; } case FormType.ChuKu: {  formcode = "CK";  break; } case FormType.LingLiao: {  formcode = "LL";  break; } case FormType.PeiChang: {  formcode = "PC";  break; } case FormType.RuKu: {  formcode = "RK";  break; } case FormType.ShengChan: {  formcode = "SC";  break; } case FormType.SunYi: {  formcode = "SY";  break; } case FormType.TuiHuo: {  formcode = "TH";  break; } case FormType.XiaoShou: {  formcode = "XS";  break; } case FormType.PeiSong: {  formcode = "PS";  break; } case FormType.ZengPin: {  formcode = "ZP";  break; } case FormType.FuKuan: {  formcode = "FK";  break; } case FormType.ShouKuan: {  formcode = "SK";  break; } } formcode += DateTime.Now.Year.ToString(); formcode += DateTime.Now.Month.ToString().Length == 1?"0" + DateTime.Now.Month.ToString() : DateTime.Now.Month.ToString(); formcode += DateTime.Now.Day.ToString().Length == 1?"0" + DateTime.Now.Day.ToString() : DateTime.Now.Day.ToString(); formcode += DateTime.Now.Hour.ToString().Length == 1?"0" + DateTime.Now.Hour.ToString() : DateTime.Now.Hour.ToString(); formcode += DateTime.Now.Minute.ToString().Length == 1?"0" + DateTime.Now.Minute.ToString() : DateTime.Now.Minute.ToString(); formcode += DateTime.Now.Second.ToString().Length == 1?"0" + DateTime.Now.Second.ToString() : DateTime.Now.Second.ToString(); if(DateTime.Now.Millisecond.ToString().Length == 1) {  formcode += "00" + DateTime.Now.Millisecond.ToString(); } else if (DateTime.Now.Millisecond.ToString().Length == 2) {  formcode += "0" + DateTime.Now.Millisecond.ToString(); } else {  formcode += DateTime.Now.Millisecond.ToString(); } return formcode;}#endregion