How to Convert date to MM/dd/yyyy?

You can't store date as your require format in datetime variable;
 
you can do:
 

string fromdate = Convert.ToDateTime(Gridtimesheetdetails.Rows[e.RowIndex].Cells[2].Text).ToString("MM/dd/yyyy");

 
Or

string fromdate = Gridtimesheetdetails.Rows[e.RowIndex].Cells[2].Text.ToString();
string dt1 = Convert.ToDateTime(fromdate).ToString("MM/dd/yyyy");

You did not add a culture. If you set the provider to null, the parser method uses the current culture.
 
Did you try this?

string dateString = "11/30/2012";
CultureInfo ci = CultureInfo.InvariantCulture;
 
DateTime myDate = DateTime.ParseExact(dateString, "MM/dd/yyyy", ci);
 

 
Or with your code:

CultureInfo ci = CultureInfo.InvariantCulture;
string fromdate = Gridtimesheetdetails.Rows[e.RowIndex].Cells[2].Text.ToString();
DateTime dt1 = DateTime.ParseExact(fromdate, "MM/dd/yyyy", ci);
 

 
On my system, current culture is de-DE and with format = null I get a exception with this date format, but whenn I set the invariant culture, it works an parses the date correct.

please try it.
 

DateTime date = new DateTime(2011, 2, 19);
string formatted = date.ToString("dd/M/yyyy");

 

or you can try this also..

public static string GetDateFromDateTime(DateTime datevalue){
    return datevalue.ToShortDateString(); 
 
//Here is a method, that takes datetime(format:01-01-2012 12:00:00) and returns //string(format: 01-01-2012) 
}