Find date interval excluding the weekends

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Hi, am trying to find the date interval between the input date and the current date excluding the weekends. But it is not working.

Am using Dateinterval :

DateDiff(DateInterval.Day,convert.ToDateTime(Filedate.ToString),convert.ToDateTime(Curdate.ToString))

I tried DateInterval.The weekend also but am getting interval as 0. Is there any other way?