protected ContestQueryParameter CreateContestQueryParameter()
{
ContestQueryParameter query = new ContestQueryParameter();
if (!string.IsNullOrEmpty(Request.QueryString["title"]))
{
query.Title = Request.QueryString["title"];
query.QueryByTitle = true;
}
if (!string.IsNullOrEmpty(Request.QueryString["author"]))
{
query.Creator = Request.QueryString["author"];
query.QueryByCreator = true;
}
if (!string.IsNullOrEmpty(Request.QueryString["status"]))
{
try
{
query.Status = ContestStatusConvert.ConvertFromString(Request.QueryString["status"]);
query.QueryByStatus = true;
}
catch (ArgumentException)
{ }
}
return(query);
}
public ActionResult ContestList()
{
// 获取查询参数。
ContestQueryParameter query = CreateContestQueryParameter();
int page = 1;
if (!string.IsNullOrEmpty(Request.QueryString["page"]))
{
if (!int.TryParse(Request.QueryString["page"], out page))
{
page = 1;
}
}
query.EnablePagedQuery = true;
query.PageQuery = new PageQueryParameter(page, ContestListItemsPerPage);
// 执行分页查询。
IEnumerable <ContestHandle> queryResult = ContestManager.Default.QueryContests(query);
List <ContestBriefModel> contests = new List <ContestBriefModel>();
foreach (ContestHandle handle in queryResult)
{
contests.Add(ContestBriefModel.FromContestHandle(handle));
}
return(QueryResult(contests));
}
public ActionResult ContestListPages()
{
ContestQueryParameter query = CreateContestQueryParameter();
query.EnablePagedQuery = true;
query.PageQuery = new PageQueryParameter(1, ContestListItemsPerPage);
return(QueryResult(ContestManager.Default.QueryPages(query)));
}
/// <summary>
/// 使用指定的查询参数计算满足条件的数据条目一共能填充多少页面。
/// </summary>
/// <param name="query">查询参数。</param>
/// <returns>满足条件的数据条目能填充多少页面。</returns>
/// <exception cref="ArgumentNullException"/>
/// <exception cref="ArgumentException"/>
/// <exception cref="ArgumentOutOfRangeException"/>
public int QueryPages(ContestQueryParameter query)
{
if (query == null)
{
throw new ArgumentNullException(nameof(query));
}
if (!query.EnablePagedQuery)
{
throw new ArgumentException("给定的查询参数未启用分页。");
}
if (query.PageQuery.ItemsPerPage <= 0)
{
throw new ArgumentOutOfRangeException(nameof(query.PageQuery.ItemsPerPage));
}
return(m_factory.WithContext(context =>
{
IQueryable <ContestEntity> set = DoQuery(context, query);
return set.GetPages(query.PageQuery.ItemsPerPage);
}));
}
/// <summary>
/// 使用给定的查询参数查询比赛句柄。
/// </summary>
/// <param name="query">封装查询参数的对象。</param>
/// <returns>一个查询结果对象，其中包含了所有查询到的比赛句柄。</returns>
/// <exception cref="ArgumentNullException"/>
/// <exception cref="ArgumentException"/>
public ReadOnlyCollection <ContestHandle> QueryContests(ContestQueryParameter query)
{
if (query == null)
{
throw new ArgumentNullException(nameof(query));
}
if (query.QueryByTitle && query.Title == null)
{
throw new ArgumentNullException(nameof(query.Title));
}
if (query.QueryByCreator && query.Creator == null)
{
throw new ArgumentNullException(nameof(query.Creator));
}
return(m_factory.WithContext(context =>
{
IQueryable <ContestEntity> set = DoQuery(context, query);
// 对数据实体对象进行排序以准备执行分页操作。
set = set.OrderByDescending(entity => entity.CreationTime);
if (query.EnablePagedQuery)
{
// 执行分页。
set = set.Page(query.PageQuery);
}
List <ContestHandle> handles = new List <ContestHandle>();
foreach (ContestEntity ent in set)
{
handles.Add(ContestHandle.FromContestEntity(ent));
}
return new ReadOnlyCollection <ContestHandle>(handles);
}));
}
private static IQueryable <ContestEntity> DoQuery(ContestDataContext context, ContestQueryParameter query)
{
IQueryable <ContestEntity> set = context.QueryAllContests();
if (query.QueryByTitle)
{
set = ContestDataContext.QueryContestsByTitle(set, query.Title);
}
if (query.QueryByCreator)
{
set = ContestDataContext.QueryContestsByCreator(set, query.Creator);
}
if (query.QueryByStatus)
{
switch (query.Status)
{
case ContestStatus.Pending:
set = ContestDataContext.QueryUnstartedContests(set);
break;
case ContestStatus.Running:
set = ContestDataContext.QueryRunningContests(set);
break;
case ContestStatus.Ended:
set = ContestDataContext.QueryEndedContests(set);
break;
default:
throw new ArgumentException(nameof(query.Status));
}
}
return(set);
}
