C# 将EF查询结果强制转换为扩展类型，扩展属性取自EF查询

我有一个标记对象：

public class Tag
{
    public int TagID { get; set; }
    public string Name { get; set; }

    public virtual ICollection<Job> Jobs { get; set; }

    public Tag()
    {
        Jobs = new HashSet<Job>();
    }
}

…我正试图从添加到每个对象的查询中检索具有Count的RecentTag对象列表：

public IEnumerable<RecentTag> GetRecentTags(int numberofdays)
{
    var tags = Jobs
        .Where(j => j.DatePosted > DateTime.Now.AddDays(-(numberofdays)))
        .SelectMany(j => j.Tags)
        .GroupBy(t => t, (k, g) => new
        {
            RecentTag = k,
            Count = g.Count()
        })
        .OrderByDescending(g => g.Count);

    // return RecentTags { TagID, Name, Count, Jobs }
}

那么，如何将查询结果转换为RecentTag类型并返回扩展对象列表

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任何帮助都将不胜感激。提前谢谢

如果作业实际上是标记的集合，并且它们实际上是RecentTag对象，那么您可以简单地使用Cast方法

var rtags = tags.Cast<RecentTags>;

我最后做了：

public IEnumerable<RecentTag> GetRecentTags(int numberofdays)
{
    DateTime startdate = DateTime.Now.AddDays(-(numberofdays));

    IEnumerable<RecentTag> tags = Jobs
        .Where(j => j.DatePosted > startdate) // Can't use DateTime.Now.AddDays in Entity query apparently
        .SelectMany(j => j.Tags)
        .GroupBy(t => t, (k, g) => new RecentTag
        {
            TagID = k.TagID,
            Name = k.Name,
            Count = g.Count()
        })
        .OrderByDescending(g => g.Count)
        .Select(a => a);

    return tags;
}

---

谢谢作业不是标签的集合。但这是我查询的切入点。

var rtags = tags.Select(x => new RecentTags() { // assign the members });

public IEnumerable<RecentTag> GetRecentTags(int numberofdays)
{
    DateTime startdate = DateTime.Now.AddDays(-(numberofdays));

    IEnumerable<RecentTag> tags = Jobs
        .Where(j => j.DatePosted > startdate) // Can't use DateTime.Now.AddDays in Entity query apparently
        .SelectMany(j => j.Tags)
        .GroupBy(t => t, (k, g) => new RecentTag
        {
            TagID = k.TagID,
            Name = k.Name,
            Count = g.Count()
        })
        .OrderByDescending(g => g.Count)
        .Select(a => a);

    return tags;
}