利用asp.net实现生成不重复订单号

#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