我写了以下扩展方法:
using System;
using System.Collections.Generic;
using System.Linq;
namespace Cortana.Extensions
{
public static class LinqExtensions
{
/// <summary>
/// Linq method to paginate data.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="source">The source.</param>
/// <param name="pageSize">Size of the page.</param>
/// <returns></returns>
public static List<IEnumerable<T>> ToPages<T>(this IEnumerable<T> source, int pageSize)
{
List<IEnumerable<T>> pagedSource = source
.Select((x, index) => new { x, index })
.GroupBy(a => a.index / pageSize)
.Select(x => x.Select(i => i.x))
.ToList();
return pagedSource;
}
}
}
被这样称呼:
using Cortana.Extensions;
...
var pagedAssessments = Model.SymptomAssessmentHistory
.Where(x => x.IsComplete())
.Where(x => (x.SymptomAssessmentUID != Model.CurrentSymptomAssessment.SymptomAssessmentUID))
.OrderByDescending(x => x.TimeTaken)
.Take(numColumnsToShow)
.ToPages(numColumnsToShow);
但是我收到以下编译器错误:
'System.Collections.Generic.IEnumerable<Cortana.Models.WebApi.SymptomAssessment>' does not contain a definition for 'ToPages' and no extension method 'ToPages' accepting a first argument of type 'System.Collections.Generic.IEnumerable<Cortana.Models.WebApi.SymptomAssessment>' could be found (are you missing a using directive or an assembly reference?)
一切似乎都已就位,我错过了什么?
事实证明,有人在我们构建的早期阶段破坏了某些东西。无论如何,感谢大家的帮助。
如果这对其他人有帮助 - 删除您的代码并确保您可以在没有它的情况下进行构建...
我遇到了类似的问题,最终注意到扩展方法在另一个程序集中声明了
internal
。不得不改成public
。
IDE 知道它在那里,甚至当我按下“转到定义”时会导航到它,但由于访问修饰符的原因,它对编译器不可见。