使用LINQ分页搜索结果SQL [英] Paginated search results with LINQ to SQL

问题描述

什么是获得与分页结果的最佳模式的的LINQ to SQL 的？

What's the best pattern to get paginated results with LINQ to SQL?

我有以下情形：

假如我想通过的描述的搜索的项目的表。我可以很容易做到：

Suppose I want to search items table by description. I can easily do:

public IQueryable<Item> FindItemsByDescription(string description)
{
   return from item in _dc.Items
          where item.Description.Contains(description);
}

现在，这将是进行分页这个结果集的最佳方式？

Now, what would be the best way to paginate this result set?

1. 我应该执行的计数的这样做是为了找出结果集的大小，然后限制按照我想要的这个查询前查询？我觉得这是要走的路。


2. 我应该执行完整的查询，以从数组大小计数，并从该数组只返回一个分页子集？我觉得这将是一个巨大的浪费时间，如果结果是够大...或者是的LINQ to SQL 的在这里做一些魔法？

1. Should I perform a count query before doing this to find out the result set size and then limit this query according to what I want? I feel like this is the way to go.
2. Should I perform the full query, take the count from the array size and return only a paginated subset from this array? I feel like this will be a huge waste of time if the resultset is big enough... Or is LINQ to SQL doing some magic here?

有没有的的LINQ to SQL 的执行此操作常见的模式？

Is there a LINQ to SQL common pattern for performing this operation?

编辑：我的必须的澄清一个小东西。我知道以和Skip方法。但是，在使用前的以和跳过后，我应该怎么得到的结果在总数该查询检索？

I must clarify a one little thing. I am aware of Take and Skip methods. But, before using Take and Skip, how should I get the total count of results that query would retrieve?

推荐答案

分页模式是非常简单的。它涉及到使用跳过（中）和Take（）扩展方法如下：

The pattern for paging is very simple. It involves the use of the Skip() and Take() extension methods as follows:

public IQueryable<Item> FindItemsByDescription(string description, int pageIndex, int pageSize)
{
   return from item in _dc.Items
          where item.Description.
          Contains(description).
          Skip((pageIndex - 1) * pageSize).
          Take(pageSize);
}

更新：：要获得总数只需使用Count（）方法：

UPDATE: To get the total count simply use the Count() method:

int totalCount = from item in _dc.Items
                 where item.Description.
                 Contains(description).Count();

int numberOfPages = (int)(totalCount/pageSize);

根据您将如何显示的记录，您可以使用numberOfPages显示为Y的页面X......第1页10等。

Depending on how you are going to the display the records, you can use the numberOfPages to display a navigation bar with "Page X of Y" ... Page 1 of 10, etc..

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