C# Date/Time String Conversion

public string GetLongDate(string Date)
{
DateTime d = Convert.ToDateTime(Date);
string format = "dddd,MMMM dd,yyyy";
string formatteddate = d.ToString(format);
return formatteddate;
}
public string GetDOBDate(string Date)
{
DateTime d = Convert.ToDateTime(Date);
string format = "MM/dd/yyyy";
string formatteddate = d.ToString(format);
return formatteddate;
}