Question

I want to calculate the date difference between form date and two date..Am using timespan to calculate the difference between two date if date difference is positive means it enter another process falls means it return error message.

My partial code is here..

  TimeSpan span = Convert.ToDateTime(txtenddate.Text).Subtract(Convert.ToDateTime(txtstartdate.Text));
        int formatted = span.Days;
        if (formatted < 1)
        {
            ScriptManager.RegisterStartupScript(this, this.GetType(), "temp", "<script language='javascript'>alert('Invalid date difference ');</script>", false);
        } 

In the above code input is end date : 30-01-2004 start date : 01-02-2002

but it returns error message : String was not recognized as a valid DateTime.

please give me a solution to solve this with out changing date format…

Answer 1

You should be using ParseExact to get the relevant DateTime.

TimeSpan ts = DateTime.ParseExact("30-01-2004", "dd-MM-yyyy", System.Globalization.CultureInfo.InvariantCulture)
                  - DateTime.ParseExact("01-02-2002", "dd-MM-yyyy", System.Globalization.CultureInfo.InvariantCulture);

While using Convert.ToDateTime it invokes DateTime.Parse which will try the conversion corresponding to the your current culture setting which as in this case doesn’t support the format of DateTime you have, so you should rely on the ParseExact whereby you know the format in which the string is expected and achieve in fetching your result.