如何使用分页方法 [英] How to use Paginate method

问题描述

我在Web API项目PaginatedList一个问题。

I have a problem with a PaginatedList in a Web API project.

在库中有一个类似的方法：

In the repository there's a method like:

public virtual PaginatedList<T> Paginate<TKey>(int pageIndex, int pageSize,
    Expression<Func<T, TKey>> keySelector,
    Expression<Func<T, bool>> predicate,
    params Expression<Func<T, object>>[] includeProperties)
{
    IQueryable<T> query = AllIncluding(includeProperties).OrderBy(keySelector);

    query = (predicate == null)
        ? query
        : query.Where(predicate);

    return query.ToPaginatedList(pageIndex, pageSize);
}

但是，当我尝试使用它，就像这样：

But, when I try to use it, like this:

var a = repository.Paginate<Region>(pageNo, pageSize, x => x.ID, null);

我得到这个错误：

I get this error:

无法键入'诠释'隐式转换为
  Domain.Entities.Dictionaries.Region

Cannot implicitly convert type 'int' to 'Domain.Entities.Dictionaries.Region'

我在做什么错了？

推荐答案

您方法签名 TKEY的，我想是排序的关键，但在你的电话你指定整个对象地区，然后指定 INT 在的KeySelectors ，这样它会尝试使用它不能编译 INT 键入为地区键入 TKEY的。

Your method signature has TKey that i suppose is a key for sorting, but in your call you are specifying the whole object Region, and then you specify int in the keySelector, so it can't compile it as it tries to use int type as Region type for TKey.

我想你的样品应该是：

repository.Paginate<int>(pageNo, pageSize, x => x.ID, null);

泛型类型 T 我想是全班指定的，所以它应该是罚款这里在调用没有指定它，因为库实例已经通用的具体。

Generic type T i suppose is specified for the whole class, so it should be fine here to not specify it in the call, as repository instance is already generic specific.

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