/// <summary>
/// 获取与给定的 <see cref="UserSortKey"/> 值对应的实体对象成员定义。
/// </summary>
/// <param name="key"><see cref="UserSortKey"/> 值。</param>
/// <returns>与给定的 <see cref="UserSortKey"/> 值对应的实体对象成员定义。</returns>
/// <exception cref="ArgumentException">给定的 <see cref="UserSortKey"/> 值无效。</exception>
public static FieldDefinition <User> GetField(this UserSortKey key)
{
LambdaExpression fieldSelector;
switch (key)
{
case UserSortKey.TotalSubmissions:
fieldSelector = (Expression <Func <User, int> >)(u => u.TotalSubmissions);
break;
case UserSortKey.TotalAcceptedSubmissions:
fieldSelector = (Expression <Func <User, int> >)(u => u.TotalAcceptedSubmissions);
break;
case UserSortKey.TotalProblemsAttempted:
fieldSelector = (Expression <Func <User, int> >)(u => u.TotalProblemsAttempted);
break;
case UserSortKey.TotalProblemsAccepted:
fieldSelector = (Expression <Func <User, int> >)(u => u.TotalProblemsAccepted);
break;
case UserSortKey.JoinTime:
fieldSelector = (Expression <Func <User, DateTime> >)(u => u.JoinTime);
break;
default:
throw new ArgumentException($"Invalid UserSortKey value: {key}");
}
return(new ExpressionFieldDefinition <User>(fieldSelector));
}
// GET: /users
public async Task <PaginatedListActionResult <UserListInfo> > GetUsers(
[FromQuery][Page] int page = 0,
[FromQuery][ItemsPerPage] int itemsPerPage = 1,
[FromQuery] UserSortKey by = UserSortKey.TotalProblemsAccepted,
[FromQuery] bool descend = true)
{
var findPipeline = new UserFindPipeline(UserFilterBuilder.Empty)
{
SortKey = by,
SortByDescending = descend,
Pagination = new Pagination(page, itemsPerPage)
};
var findResult = await _repo.Users.FindManyAsync(findPipeline);
var models = findResult.ResultSet.Select(e => _mapper.Map <User, UserListInfo>(e));
return(findResult.TotalCount, models);
}