C# 在购物车系统中生成不重复的订单号

C# 在购物车系统中生成不重复的订单号，订单号在购物过程中起到了很好的识别作用，更方便的有利于工作人员识别商品

#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