与LINQ和Lambda一起在哪里

与LINQ和Lambda一起/在哪里

我发现，如果您熟悉SQL语法，则使用LINQ查询语法会更清晰，更自然，并且更容易发现错误：

var id = 1;var query =   from post in database.Posts   join meta in database.Post_metas on post.ID equals meta.Post_ID   where post.ID == id   select new { Post = post, meta = meta };

但是，如果您真的很喜欢使用lambda，那么您的语法就会有些偏离。这是使用LINQ扩展方法的相同查询：

var id = 1;var query = database.Posts    // your starting point - table in the "from" statement   .Join(database.Post_metas, // the source table of the inner join      post => post.ID,        // Select the primary key (the first part of the "on" clause in an sql "join" statement)      meta => meta.Post_ID,   // Select the foreign key (the second part of the "on" clause)      (post, meta) => new { Post = post, meta = meta }) // selection   .Where(postAndmeta => postAndmeta.Post.ID == id);    // where statement