介绍
LINQ to JavaScript (JSLINQ) 是LINQ在JavaScript上的实现。其为JS的Array对象上增加了一系列扩展方法。如果你要用到Array,那么你就可以使用JSLINQ。
如果你还不了解什么是LINQ;LINQ是.NET Framework 3.5支持的新特性,其可以允许像SQL查询一样操作各种类型的数据。LINQ to JavaScript就是专门为数组提供查询的能力。
用法示例
var
myList
=
[
{FirstName: " Chris " ,LastName: " Pearson " },
{FirstName: " Kate " ,LastName: " Johnson " },
{FirstName: " Josh " ,LastName: " Sutherland " },
{FirstName: " John " ,LastName: " Ronald " },
{FirstName: " Steve " ,LastName: " Pinkerton " }
];
var exampleArray = From(myList).
Where( " item.FirstName == 'Chris' " ).
OrderBy( " item.FirstName " ).
Select( " item.FirstName " );
{FirstName: " Chris " ,LastName: " Pearson " },
{FirstName: " Kate " ,LastName: " Johnson " },
{FirstName: " Josh " ,LastName: " Sutherland " },
{FirstName: " John " ,LastName: " Ronald " },
{FirstName: " Steve " ,LastName: " Pinkerton " }
];
var exampleArray = From(myList).
Where( " item.FirstName == 'Chris' " ).
OrderBy( " item.FirstName " ).
Select( " item.FirstName " );
使用LINQ to JavaScript
我们使用下面的数组来作为例子演示:
var
myList
=
[
{FirstName: " Chris " ,LastName: " Pearson " },
{FirstName: " Kate " ,LastName: " Johnson " },
{FirstName: " Josh " ,LastName: " Sutherland " },
{FirstName: " John " ,LastName: " Ronald " },
{FirstName: " Steve " ,LastName: " Pinkerton " }
];
{FirstName: " Chris " ,LastName: " Pearson " },
{FirstName: " Kate " ,LastName: " Johnson " },
{FirstName: " Josh " ,LastName: " Sutherland " },
{FirstName: " John " ,LastName: " Ronald " },
{FirstName: " Steve " ,LastName: " Pinkerton " }
];
就像在.NET中一样的使用From操作符
From操作符不是必须的,写上的话可以使得看上去更像LINQ的语法。
var
example
=
From(myList);
使用Where操作符来限定查询条件
如下所示,我们会得到数组里全部属性FirstName值为Chris的对象。
//
传入的是查询表达式
var whereExample1 = From(myList).
Where( " item.FirstName == 'Chris' " );
// 传入的是查询函数方法
var whereExample2 = From(myList).
Where( function (item){ return item.FirstName == ' Chris ' ;});
var whereExample1 = From(myList).
Where( " item.FirstName == 'Chris' " );
// 传入的是查询函数方法
var whereExample2 = From(myList).
Where( function (item){ return item.FirstName == ' Chris ' ;});
使用Select操作符来指定返回的数据
如下所示,我们会得到数组里的每个元素的FirstName属性。
// 传入的是查询表达式
var selectTest1 = From(myList).
Select( " item.FirstName " );
// 传入的是查询函数方法
var selectTest2 = From(myList).
Select( function (item){ return item.FirstName;});
使用OrderBy操作符来决定怎样对数组中的元素进行排序
var selectTest1 = From(myList).
Select( " item.FirstName " );
// 传入的是查询函数方法
var selectTest2 = From(myList).
Select( function (item){ return item.FirstName;});
如下所示,我们会得到按FirstName属性排序后的数组。
// 传入的是查询表达式
var sortTest1 = From(myList).
OrderBy( " item.FirstName " );
// 传入的是查询函数方法
var sortTest1 = From(myList).
OrderBy( function (item){ return item.FirstName});
var sortTest1 = From(myList).
OrderBy( " item.FirstName " );
// 传入的是查询函数方法
var sortTest1 = From(myList).
OrderBy( function (item){ return item.FirstName});
HomePage: http://www.codeplex.com/JSLINQ
Download: http://files.cnblogs.com/Icebird/JSLINQ_withSDK_v1.03.rar (2008-02-10)