c# - How do I generate an ID that is garunteed to be unique? -

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• unique random string generation 11 answers

i need garuntee uniqueness of id. if there's 1 in 1 trillion chance of there being dupe, cannot use it.

but don't feel going ends of earth find solution either. have spent time looking this, , have found date isn't able garuntee me unique id.

so thought use simple, this:

    public static string generateitemid()     {         string year = datetime.now.year.tostring(),              month = datetime.now.month.tostring(),              day = datetime.now.day.tostring(),              hour = datetime.now.hour.tostring(),              minute = datetime.now.minute.tostring(),              second = datetime.now.second.tostring(),              millisecond = datetime.now.millisecond.tostring();          return year + month + day + hour + minute + second + millisecond;     } 

my logic here is: each new ui generated can not possibly same of previous ones. wondered if possible pc generate 2 or more of these id's within same millisecond? naturally, looked in intellisense nanosecond property, doesn't exist.

how can generate id garunteed unique?

var id = guid.newguid();  

i believe create unique id.