模型字段（在django中）和序列化器字段之间的区别（在django rest框架中）(Difference between model fields(in django) and serializer fields(in django rest framework))

 您可以按月和按年对TimeSheet记录进行分组，如下所示： 
 
DateTimeFormatInfo dtfi = new DateTimeFormatInfo();

// gets the records grouped based on Year and Month. 
// Creates an object of IEnumerable<IGrouping<>> type
var groupedByMonth = result
                        .OrderByDescending(x => x.Date)
                        .GroupBy(x => new { x.Date.Year, x.Date.Month }).ToList();


// gets the months names in a list
List<string> monthNames = groupedByMonth
                    .Select(a => dtfi.GetAbbreviatedMonthName(a.Key.Month))
                    .ToList();

// gets the total hours per month
List<int> hoursPerMonth = groupedByMonth
                        .Select(a => a.Sum(p => p.Hours))
                        .ToList();


ArrayList xValue = new ArrayList(monthNames);
ArrayList yValue = new ArrayList(hoursPerMonth);
 
 我正在使用DateTimeFormatInfo来获取月份的名称。 没有这个你也可以实现这个目标： 
 
List<string> monthNames = groupedByMonth
                    .Select(a => a.FirstOrDefault().Date.ToString("MMMM"))
                    .ToList();

You can group the TimeSheet records by month and year like this:
 
DateTimeFormatInfo dtfi = new DateTimeFormatInfo();

// gets the records grouped based on Year and Month. 
// Creates an object of IEnumerable<IGrouping<>> type
var groupedByMonth = result
                        .OrderByDescending(x => x.Date)
                        .GroupBy(x => new { x.Date.Year, x.Date.Month }).ToList();


// gets the months names in a list
List<string> monthNames = groupedByMonth
                    .Select(a => dtfi.GetAbbreviatedMonthName(a.Key.Month))
                    .ToList();

// gets the total hours per month
List<int> hoursPerMonth = groupedByMonth
                        .Select(a => a.Sum(p => p.Hours))
                        .ToList();


ArrayList xValue = new ArrayList(monthNames);
ArrayList yValue = new ArrayList(hoursPerMonth);
 
I'm using DateTimeFormatInfo to get the month's name. You can also achieve this without this:
 
List<string> monthNames = groupedByMonth
                    .Select(a => a.FirstOrDefault().Date.ToString("MMMM"))
                    .ToList();