[英]C# Pass a generic delegate to constructor
我是C#的新手,我试图找到一种将通用委托传递给构造函数的方法。
调用show端点时,如果存在分页,则端点应返回Page实例。 创建Page实例时,委托方法应作为构造函数参数之一传递。 ShowsEndpoints将托管许多端点,并且其中许多端点使用分页。 我只想使用一个类来处理所有端点。
public partial class ShowsEndpoints : Endpoint
{
public Func<Task<IEnumerable<object>>> FetchPopularShowsAsyncDelegate;
public Func<Task<IEnumerable<object>>> FetchTrendingShowsAsyncDelegate;
public Func<Task<IEnumerable<object>>> FetchMostWatchedShowsAsyncDelegate;
public async Task<IEnumerable<object>> FetchPopularShowsAsync(int page = 1, int limit = 20)
{
return await SendAsync(new PopularShowsRequest(page, limit));
}
public async Task<IEnumerable<object>> FetchTrendingShowsAsync(int page = 1, int limit = 20)
{
return await SendAsync(new TrendingShowsRequest(page, limit));
}
public async Task<IEnumerable<object>> FetchMostWatchedShowsAsync(int page = 1, int limit = 20)
{
return await SendAsync(new MostWatchedShowsRequest(page, limit));
}
}
页面类,如果存在下一页,它将调用委托以获取下一页。
public class Page<TItem, TDelegate>
{
private TDelegate _delegateCommand;
public int CurrentPage { get; }
public int TotalPages { get; }
public int PageItemsCount { get; }
public int TotalItemsCount { get; }
public IEnumerable<TItem> Items { get; }
public Page(int page, int totalPages, int itemsCount, int totalItemsCount, IEnumerable<TItem> items, TDelegate delegateCommand)
{
CurrentPage = page;
TotalPages = totalPages;
PageItemsCount = itemsCount;
TotalItemsCount = totalItemsCount;
Items = items;
_delegateCommand = delegateCommand;
}
public bool HasNext()
{
return CurrentPage <= TotalPages;
}
public bool HasPrevious()
{
return CurrentPage >= 1;
}
public Page<TItem, TDelegate> Next()
{
// call _delegateCommand to fetch the next page items
}
public Page<TItem, TDelegate> Previous()
{
// call _delegateCommand to fetch the previous page items
}
}
可能吗 ?
谢谢。
编辑
我已经更新了班级代码,以更好地理解我的问题。 我有3个与它们的委托相关联的端点,并且我希望Page
类使用这3个委托中的任何一个使用相同的代码来避免重复。 因此_delegateCommand
可以是FetchPopularShowsAsyncDelegate
, FetchTrendingShowsAsyncDelegate
或FetchMostWatchedShowsAsyncDelegate
。
我不确定我_delegateCommand
正确使用_delegateCommand
的目的-我想应该是返回IEnumerable<TItem>
。 如果是这样,那么您可以像这样精确地声明它,那么您就不必引入另一个通用参数:
public class Page<TItem>
{
private Func<IEnumerable<TItem>>_delegateCommand;
public int CurrentPage { get; }
public int TotalPages { get; }
public int PageItemsCount { get; }
public int TotalItemsCount { get; }
public IEnumerable<TItem> Items { get; }
public Page(int page, int totalPages, int itemsCount,
int totalItemsCount, IEnumerable<TItem> items,
Func<IEnumerable<TItem>> delegateCommand)
{
CurrentPage = page;
TotalPages = totalPages;
PageItemsCount = itemsCount;
TotalItemsCount = totalItemsCount;
Items = items;
_delegateCommand = delegateCommand;
}
public bool HasNext()
{
return CurrentPage <= TotalPages;
}
public bool HasPrevious()
{
return CurrentPage >= 1;
}
}
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