对数据进行排序

项目
02/21/2013

排序操作按一个或多个特性对序列的元素进行排序。第一个排序条件对元素执行主要排序。通过指定第二个排序条件，可以对各个主要排序组中的元素进行排序。

下图演示对一个字符序列执行按字母排序操作的结果。

LINQ 排序操作

下面一节中列出了对数据进行排序的标准查询运算符方法。

方法

方法名	说明	C# 查询表达式语法	Visual Basic 查询表达式语法	更多信息
OrderBy	按升序对值进行排序。	orderby	Order By	Enumerable.OrderBy Queryable.OrderBy
OrderByDescending	按降序对值进行排序。	orderby … descending	Order By … Descending	Enumerable.OrderByDescending Queryable.OrderByDescending
ThenBy	按升序执行次要排序。	orderby …, …	Order By …, …	Enumerable.ThenBy Queryable.ThenBy
ThenByDescending	按降序执行次要排序。	orderby …, … descending	Order By …, … Descending	Enumerable.ThenByDescending Queryable.ThenByDescending
Reverse	颠倒集合中的元素的顺序。	不适用。	不适用。	Enumerable.Reverse<TSource> Queryable.Reverse<TSource>

查询表达式语法示例

主要排序示例

主要升序排序

下面的示例演示如何在 LINQ 查询中使用 orderby（在 Visual Basic 中为 Order By）子句来按字符串长度对数组中的字符串进行升序排序。


        Dim words = {"the", "quick", "brown", "fox", "jumps"}

        Dim sortQuery = From word In words 
                        Order By word.Length 
                        Select word

        Dim sb As New System.Text.StringBuilder()
        For Each str As String In sortQuery
            sb.AppendLine(str)
        Next

        ' Display the results.
        MsgBox(sb.ToString())

        ' This code produces the following output:

        ' the
        ' fox
        ' quick
        ' brown
        ' jumps


            string[] words = { "the", "quick", "brown", "fox", "jumps" };

            IEnumerable<string> query = from word in words
                                        orderby word.Length
                                        select word;

            foreach (string str in query)
                Console.WriteLine(str);

            /* This code produces the following output:

                the
                fox
                quick
                brown
                jumps
            */

主要降序排序

下一个示例演示如何在 LINQ 查询中使用 orderby descending（在 Visual Basic 中为 Order By Descending）子句来按字符串的第一个字母对字符串进行降序排序。


        Dim words = {"the", "quick", "brown", "fox", "jumps"}

        Dim sortQuery = From word In words 
                        Order By word.Substring(0, 1) Descending 
                        Select word

        Dim sb As New System.Text.StringBuilder()
        For Each str As String In sortQuery
            sb.AppendLine(str)
        Next

        ' Display the results.
        MsgBox(sb.ToString())

        ' This code produces the following output:

        ' the
        ' quick
        ' jumps
        ' fox
        ' brown


            string[] words = { "the", "quick", "brown", "fox", "jumps" };

            IEnumerable<string> query = from word in words
                                        orderby word.Substring(0, 1) descending
                                        select word;

            foreach (string str in query)
                Console.WriteLine(str);

            /* This code produces the following output:

                the
                quick
                jumps
                fox
                brown
            */

次要排序示例

次要升序排序

下面的示例演示如何在 LINQ 查询中使用 orderby（在 Visual Basic 中为 Order By）子句来对数组中的字符串执行主要和次要排序。首先按字符串长度，其次按字符串的第一个字母，对字符串进行升序排序。


        Dim words = {"the", "quick", "brown", "fox", "jumps"}

        Dim sortQuery = From word In words 
                        Order By word.Length, word.Substring(0, 1) 
                        Select word

        Dim sb As New System.Text.StringBuilder()
        For Each str As String In sortQuery
            sb.AppendLine(str)
        Next

        ' Display the results.
        MsgBox(sb.ToString())

        ' This code produces the following output:

        ' fox
        ' the
        ' brown
        ' jumps
        ' quick


            string[] words = { "the", "quick", "brown", "fox", "jumps" };

            IEnumerable<string> query = from word in words
                                        orderby word.Length, word.Substring(0, 1)
                                        select word;

            foreach (string str in query)
                Console.WriteLine(str);

            /* This code produces the following output:

                fox
                the
                brown
                jumps
                quick
            */

次要降序排序

下一个示例演示如何在 LINQ 查询中使用 orderby descending（在 Visual Basic 中为 Order By Descending）子句来按升序执行主要排序，按降序执行次要排序。首先按字符串长度，其次按字符串的第一个字母，对字符串进行排序。


        Dim words = {"the", "quick", "brown", "fox", "jumps"}

        Dim sortQuery = From word In words 
                        Order By word.Length, word.Substring(0, 1) Descending 
                        Select word

        Dim sb As New System.Text.StringBuilder()
        For Each str As String In sortQuery
            sb.AppendLine(str)
        Next

        ' Display the results.
        MsgBox(sb.ToString())

        ' This code produces the following output:

        ' fox
        ' the
        ' quick
        ' jumps
        ' brown


            string[] words = { "the", "quick", "brown", "fox", "jumps" };

            IEnumerable<string> query = from word in words
                                        orderby word.Length, word.Substring(0, 1) descending
                                        select word;

            foreach (string str in query)
                Console.WriteLine(str);

            /* This code produces the following output:

                the
                fox
                quick
                jumps
                brown
            */

请参见

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