Queryable.ThenByDescending Queryable.ThenByDescending Queryable.ThenByDescending Queryable.ThenByDescending Method

定義

シーケンス内の後続の要素を降順で配置します。Performs a subsequent ordering of the elements in a sequence in descending order.

オーバーロード

ThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>) ThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>) ThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>) ThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>)

キーに従って、シーケンス内の後続の要素を降順で配置します。Performs a subsequent ordering of the elements in a sequence in descending order, according to a key.

ThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>) ThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>) ThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>) ThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>)

指定された比較子を使用して、シーケンス内の後続の要素を降順で配置します。Performs a subsequent ordering of the elements in a sequence in descending order by using a specified comparer.

ThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>) ThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>) ThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>) ThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>)

キーに従って、シーケンス内の後続の要素を降順で配置します。Performs a subsequent ordering of the elements in a sequence in descending order, according to a key.

public:
generic <typename TSource, typename TKey>
[System::Runtime::CompilerServices::Extension]
 static System::Linq::IOrderedQueryable<TSource> ^ ThenByDescending(System::Linq::IOrderedQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, TKey> ^> ^ keySelector);
public static System.Linq.IOrderedQueryable<TSource> ThenByDescending<TSource,TKey> (this System.Linq.IOrderedQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,TKey>> keySelector);
static member ThenByDescending : System.Linq.IOrderedQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, 'Key>> -> System.Linq.IOrderedQueryable<'Source>
<Extension()>
Public Function ThenByDescending(Of TSource, TKey) (source As IOrderedQueryable(Of TSource), keySelector As Expression(Of Func(Of TSource, TKey))) As IOrderedQueryable(Of TSource)

型パラメーター

TSource

source の要素の型。The type of the elements of source.

TKey

keySelector で表された関数によって返されるキーの型。The type of the key returned by the function represented by keySelector.

パラメーター

source
IOrderedQueryable<TSource>

並べ替える要素を格納している IOrderedQueryable<T>An IOrderedQueryable<T> that contains elements to sort.

keySelector
Expression<Func<TSource,TKey>>

各要素からキーを抽出する関数。A function to extract a key from each element.

戻り値

要素がキーに従って降順に並べ替えられている IOrderedQueryable<T>An IOrderedQueryable<T> whose elements are sorted in descending order according to a key.

例外

source または keySelectornull です。source or keySelector is null.

注釈

このメソッドには、型引数が型Expression<TDelegate>の1つ以上の型のFunc<T,TResult>パラメーターが少なくとも1つ含まれています。This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. これらのパラメーターの場合は、ラムダ式を渡すことができ、にExpression<TDelegate>コンパイルされます。For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

メソッドThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>)は、構築MethodCallExpressionされたThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>)ジェネリックメソッドとして呼び出し元を表すを生成します。The ThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>) method generates a MethodCallExpression that represents calling ThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>) itself as a constructed generic method. MethodCallExpressionに、 IQueryProvider CreateQuery<TElement>(Expression) パラメーターsourceProviderプロパティによって表されるのメソッドにを渡します。It then passes the MethodCallExpression to the CreateQuery<TElement>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter. を呼び出しCreateQuery<TElement>(Expression)た結果が型IOrderedQueryable<T>にキャストされ、が返されます。The result of calling CreateQuery<TElement>(Expression) is cast to type IOrderedQueryable<T> and returned.

呼び出しThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>)を表す式ツリーを実行した結果として発生するクエリ動作は、 sourceパラメーターの型の実装によって異なります。The query behavior that occurs as a result of executing an expression tree that represents calling ThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>) depends on the implementation of the type of the source parameter. 期待される動作は、の各要素source sourceに対してを呼び出すkeySelectorことによって取得したキーに基づいて、の要素の2番目の並べ替えを降順で実行することです。The expected behavior is that it performs a secondary sort of the elements of source in descending order, based on the key obtained by invoking keySelector on each element of source. 以前に確立されたすべての並べ替え順序は保持されます。All previously established sort orders are preserved.

ThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>) ThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>) ThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>) ThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>)

指定された比較子を使用して、シーケンス内の後続の要素を降順で配置します。Performs a subsequent ordering of the elements in a sequence in descending order by using a specified comparer.

public:
generic <typename TSource, typename TKey>
[System::Runtime::CompilerServices::Extension]
 static System::Linq::IOrderedQueryable<TSource> ^ ThenByDescending(System::Linq::IOrderedQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, TKey> ^> ^ keySelector, System::Collections::Generic::IComparer<TKey> ^ comparer);
public static System.Linq.IOrderedQueryable<TSource> ThenByDescending<TSource,TKey> (this System.Linq.IOrderedQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,TKey>> keySelector, System.Collections.Generic.IComparer<TKey> comparer);
static member ThenByDescending : System.Linq.IOrderedQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, 'Key>> * System.Collections.Generic.IComparer<'Key> -> System.Linq.IOrderedQueryable<'Source>
<Extension()>
Public Function ThenByDescending(Of TSource, TKey) (source As IOrderedQueryable(Of TSource), keySelector As Expression(Of Func(Of TSource, TKey)), comparer As IComparer(Of TKey)) As IOrderedQueryable(Of TSource)

型パラメーター

TSource

source の要素の型。The type of the elements of source.

TKey

keySelector 関数によって返されるキーの型。The type of the key that is returned by the keySelector function.

パラメーター

source
IOrderedQueryable<TSource>

並べ替える要素を格納している IOrderedQueryable<T>An IOrderedQueryable<T> that contains elements to sort.

keySelector
Expression<Func<TSource,TKey>>

各要素からキーを抽出する関数。A function to extract a key from each element.

comparer
IComparer<TKey>

キーを比較する IComparer<T>An IComparer<T> to compare keys.

戻り値

要素がキーに従って降順に並べ替えられているコレクション。A collection whose elements are sorted in descending order according to a key.

例外

sourcekeySelector、または comparer は、null です。source or keySelector or comparer is null.

次のコード例は、を使用ThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>)して、カスタム比較子を使用してシーケンス内の要素の2番目の並べ替えを降順で実行する方法を示しています。The following code example demonstrates how to use ThenByDescending<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>) to perform a secondary ordering of the elements in a sequence in descending order by using a custom comparer.

public class CaseInsensitiveComparer : IComparer<string>
{
    public int Compare(string x, string y)
    {
        return string.Compare(x, y, true);
    }
}

public static void ThenByDescendingEx1()
{
    string[] fruits = 
    { "apPLe", "baNanA", "apple", "APple", "orange", "BAnana", "ORANGE", "apPLE" };

    // Sort the strings first ascending by their length and 
    // then descending using a custom case insensitive comparer.
    IEnumerable<string> query =
        fruits.AsQueryable()
        .OrderBy(fruit => fruit.Length)
        .ThenByDescending(fruit => fruit, new CaseInsensitiveComparer());

    foreach (string fruit in query)
        Console.WriteLine(fruit);
}

/*
    This code produces the following output:

    apPLe
    apple
    APple
    apPLE
    orange
    ORANGE
    baNanA
    BAnana
*/

Class CaseInsensitiveComparer
    Implements IComparer(Of String)

    Function Compare(ByVal x As String, ByVal y As String) As Integer _
        Implements IComparer(Of String).Compare

        ' Compare values and ignore case.
        Return String.Compare(x, y, True)
    End Function
End Class

Sub ThenByDescendingEx1()
    Dim fruits() As String = _
        {"apPLe", "baNanA", "apple", "APple", "orange", "BAnana", "ORANGE", "apPLE"}

    ' Sort the strings first ascending by their length and 
    ' then descending by using a custom case insensitive comparer.
    Dim query = fruits.AsQueryable() _
        .OrderBy(Function(fruit) fruit.Length) _
        .ThenByDescending(Function(fruit) fruit, New CaseInsensitiveComparer())

    Dim output As New System.Text.StringBuilder
    For Each fruit As String In query
        output.AppendLine(fruit)
    Next

    ' Display the results.
    MsgBox(output.ToString())
End Sub

' This code produces the following output:

' apPLe
' apple
' APple
' apPLE
' orange
' ORANGE
' baNanA
' BAnana

注釈

このメソッドには、型引数が型Expression<TDelegate>の1つ以上の型のFunc<T,TResult>パラメーターが少なくとも1つ含まれています。This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. これらのパラメーターの場合は、ラムダ式を渡すことができ、にExpression<TDelegate>コンパイルされます。For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

メソッドThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>)は、構築MethodCallExpressionされたThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>)ジェネリックメソッドとして呼び出し元を表すを生成します。The ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>) method generates a MethodCallExpression that represents calling ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>) itself as a constructed generic method. MethodCallExpressionに、 IQueryProvider CreateQuery<TElement>(Expression) パラメーターsourceProviderプロパティによって表されるのメソッドにを渡します。It then passes the MethodCallExpression to the CreateQuery<TElement>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter. を呼び出しCreateQuery<TElement>(Expression)た結果が型IOrderedQueryable<T>にキャストされ、が返されます。The result of calling CreateQuery<TElement>(Expression) is cast to type IOrderedQueryable<T> and returned.

呼び出しThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>)を表す式ツリーを実行した結果として発生するクエリ動作は、 sourceパラメーターの型の実装によって異なります。The query behavior that occurs as a result of executing an expression tree that represents calling ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>) depends on the implementation of the type of the source parameter. 期待される動作は、の各要素source sourceに対してを呼び出すkeySelectorことによって取得したキーに基づいて、の要素の2番目の並べ替えを降順で実行することです。The expected behavior is that it performs a secondary sort of the elements of source in descending order, based on the key obtained by invoking keySelector on each element of source. 以前に確立されたすべての並べ替え順序は保持されます。All previously established sort orders are preserved. パラメーター comparerは、キー値の比較に使用されます。The comparer parameter is used to compare key values.

適用対象