废话不数,直入主题,Linq下怎么进行分页
很多学习Linq的朋友肯定有自己所不同的方法,考虑这个问题我所想到的是
用Take(),Skip(),TakeWhile(),SkipUntil()中的方法来实现
首先看Take()是否可用
Take方法的作用是从结果中取固定数量的值,
MydbDataContext mydb=new MydbDataContext("server=.;database=mydb");
var query=from p in mydb.Products
orderby p.id descending
select p;//取出Products中所用的项按降序排列
如果直接用take()
var q=query.take(n) 这样只能取出前条n记录,但是还是让我们看到了分页的曙光,还是还有个skip吗,skip可以取出除去满足条件的剩下的记录。如果我们要把数据以每页pagesize的数量来进行分页,很简单,很skip(pagersize*pagenum)然后在剩下的记录中take(pagesize)不就得到了想要的数据了么。
varq=query.skip(pagesize*pagenum).take(pagesize) 就这么简单。
希望朋友们提供更好的方法来进行分页,同时对这个方法的优劣性,进行批评指导
附上运行时生成的SQL(感谢:紫色阴影 、Boler Guo )
sql server2000:
SELECT TOP 20 [t0].[CustomerID], [t0].[CompanyName], [t0].[ContactName], [t0].[ContactTitle], [t0].[Address], [t0].[City], [t0].[Region], [t0].[PostalCode], [t0].[Country], [t0].[Phone], [t0].[Fax]
FROM [dbo].[Customers] AS [t0]
WHERE NOT (EXISTS(
SELECT NULL AS [EMPTY]
FROM (
SELECT TOP 10 [t1].[CustomerID]
FROM [dbo].[Customers] AS [t1]
) AS [t2]
WHERE [t0].[CustomerID] = [t2].[CustomerID]
))
sql server 2005
SELECT TOP 10 [t1].[CustomerID], [t1].[CompanyName], [t1].[ContactName], [t1].[ContactTitle], [t1].[Address], [t1].[City], [t1].[Region], [t1].[PostalCode], [t1].[Country], [t1].[Phone], [t1].[Fax]
FROM (
SELECT ROW_NUMBER() OVER (ORDER BY [t0].[ContactName]) AS [ROW_NUMBER], [t0].[CustomerID], [t0].[CompanyName], [t0].[ContactName], [t0].[ContactTitle], [t0].[Address], [t0].[City], [t0].[Region], [t0].[PostalCode], [t0].[Country], [t0].[Phone], [t0].[Fax]
FROM [dbo].[Customers] AS [t0]
) AS [t1]
WHERE [t1].[ROW_NUMBER] > @p0
ORDER BY [t1].[ContactName]
-- @p0: Input Int32 (Size = 0; Prec = 0; Scale = 0) [50]
-- Context: SqlProvider(Sql2005) Model: AttributedMetaModel Build: 3.5.20XXX.X