无法转换的IQueryable<>到IOrderedQueryable错误 [英] Cannot convert IQueryable<> to IOrderedQueryable error

问题描述

我有以下的LINQ代码：

I have the following LINQ code:

    var posts = (from p in db.Posts
         .Include("Site")
         .Include("PostStatus")
        where p.Public == false
        orderby p.PublicationTime 
        select p);

        if (!chkShowIgnored.Checked) {
            posts = posts.Where(p => p.PostStatus.Id != 90);
        }

这最后一行（额外的位置）是给我的错误：

That last line (the extra where) is giving me the error:

无法隐式转换类型'System.Linq.IQueryable'到'System.Linq.IOrderedQueryable。

Cannot implicitly convert type 'System.Linq.IQueryable' to 'System.Linq.IOrderedQueryable'.

我不太清楚这是什么意思......结果
为什么会出现这个错误？结果
看来，一旦我添加了排序依据子句来查询，在这之前它编译罚款，所以我有一种预感的是怎么回事，但我不能完全把我的手指进去。

I'm not sure what this means...
Why am I getting this error?
It appeared once I added the "orderby" clause to the query, before that it compiled fine, so I have kind of a hunch of what is going on, but I can't quite put my finger into it.

推荐答案

尝试宣告帖子专门为的IQueryable<邮政> ，而不是 VAR （将拿起 IOrderedQueryable<邮政方式> （它仍将是订购）

Try declaring posts specifically as IQueryable<Post> rather than var (which will pick up the IOrderedQueryable<Post> (it will still be ordered).

另外，重新架构，所以我们下令在最后，使我们能够在其中，在中间（可选）带来的：

Alternatively, re-structure it so we order at the end, allowing us to (optionally) bring in the where in the middle:

var posts = from p in db.Posts
             .Include("Site")
             .Include("PostStatus")
            where p.Public == false
            select p);

if (!chkShowIgnored.Checked) {
    posts = posts.Where(p => p.PostStatus.Id != 90);
}
var finalQuery = posts.OrderBy(p => p.PublicationTime);

（显然，我们来看看 finalQuery ）

有示数的原因是，目前你有（本质）：

The reason it is erroring is that currently you have (essentially):

IOrderedQueryable<Post> posts = {snip};
...
posts = {something (Where) that returns IQueryable<Post>}

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