Queryable.ThenBy 方法

public:
generic <typename TSource, typename TKey>
[System::Runtime::CompilerServices::Extension]
 static System::Linq::IOrderedQueryable<TSource> ^ ThenBy(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> ThenBy<TSource,TKey> (this 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> ThenBy<TSource,TKey> (this System.Linq.IOrderedQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,TKey>> keySelector, System.Collections.Generic.IComparer<TKey>? comparer);

static member ThenBy : System.Linq.IOrderedQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, 'Key>> * System.Collections.Generic.IComparer<'Key> -> System.Linq.IOrderedQueryable<'Source>

<Extension()>
Public Function ThenBy(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)

類型參數

參數

傳回

IOrderedQueryable<TSource>

依據索引鍵排序其項目的 IOrderedQueryable<T>。An IOrderedQueryable<T> whose elements are sorted according to a key.

例外狀況

備註

這個方法至少有一個類型的參數 Expression<TDelegate> ，其型別引數是其中一種 Func<T,TResult> 類型。This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. 針對這些參數，您可以傳入 lambda 運算式，並將其編譯為 Expression<TDelegate> 。For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>)方法 MethodCallExpression 會產生，代表呼叫 ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>) 本身做為已建立的泛型方法。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. 然後，它會將傳遞 MethodCallExpression 給以 CreateQuery<TElement>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider source 。It then passes the MethodCallExpression to the CreateQuery<TElement>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter. 呼叫的結果 CreateQuery<TElement>(Expression) 會轉換成型別 IOrderedQueryable<T> 並傳回。The result of calling CreateQuery<TElement>(Expression) is cast to type IOrderedQueryable<T> and returned.

執行表示呼叫的運算式樹狀架構所產生的查詢行為， ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>) 取決於參數類型的實作為 source 。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. 預期的行為是它會 source 根據在 keySelector 的每個專案上叫用所取得的索引鍵，執行專案的次要排序 source 。The expected behavior is that it performs a secondary sort of the elements of source based on the key obtained by invoking keySelector on each element of source. 所有先前建立的排序次序都會保留下來。All previously established sort orders are preserved. comparer參數是用來比較索引鍵值。The comparer parameter is used to compare key values.

public:
generic <typename TSource, typename TKey>
[System::Runtime::CompilerServices::Extension]
 static System::Linq::IOrderedQueryable<TSource> ^ ThenBy(System::Linq::IOrderedQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, TKey> ^> ^ keySelector);

public static System.Linq.IOrderedQueryable<TSource> ThenBy<TSource,TKey> (this System.Linq.IOrderedQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,TKey>> keySelector);

static member ThenBy : System.Linq.IOrderedQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, 'Key>> -> System.Linq.IOrderedQueryable<'Source>

<Extension()>
Public Function ThenBy(Of TSource, TKey) (source As IOrderedQueryable(Of TSource), keySelector As Expression(Of Func(Of TSource, TKey))) As IOrderedQueryable(Of TSource)

類型參數

參數

傳回

IOrderedQueryable<TSource>

依據索引鍵排序其項目的 IOrderedQueryable<T>。An IOrderedQueryable<T> whose elements are sorted according to a key.

例外狀況

範例

下列程式碼範例示範如何使用 ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>) 來執行序列中元素的次要順序。The following code example demonstrates how to use ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>) to perform a secondary ordering of the elements in a sequence.

string[] fruits = { "grape", "passionfruit", "banana", "apple",
                      "orange", "raspberry", "mango", "blueberry" };

// Sort the strings first by their length and then
// alphabetically by passing the identity selector function.
IEnumerable<string> query =
    fruits.AsQueryable()
    .OrderBy(fruit => fruit.Length).ThenBy(fruit => fruit);

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

/*
    This code produces the following output:

    apple
    grape
    mango
    banana
    orange
    blueberry
    raspberry
    passionfruit
*/

Dim fruits() As String = _
    {"grape", "passionfruit", "banana", "mango", _
     "orange", "raspberry", "apple", "blueberry"}

' Sort the strings first by their length and then 
' alphabetically by passing the identity selector function.
Dim query = fruits.AsQueryable() _
    .OrderBy(Function(fruit) fruit.Length).ThenBy(Function(fruit) fruit)

' Display the results.
Dim output As New System.Text.StringBuilder
For Each fruit As String In query
    output.AppendLine(fruit)
Next
MsgBox(output.ToString())

'This code produces the following output:

'apple
'grape
'mango
'banana
'orange
'blueberry
'raspberry
'passionfruit

備註

這個方法至少有一個類型的參數 Expression<TDelegate> ，其型別引數是其中一種 Func<T,TResult> 類型。This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. 針對這些參數，您可以傳入 lambda 運算式，並將其編譯為 Expression<TDelegate> 。For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>)方法 MethodCallExpression 會產生，代表呼叫 ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>) 本身做為已建立的泛型方法。The ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>) method generates a MethodCallExpression that represents calling ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>) itself as a constructed generic method. 然後，它會將傳遞 MethodCallExpression 給以 CreateQuery<TElement>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider source 。It then passes the MethodCallExpression to the CreateQuery<TElement>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter. 呼叫的結果 CreateQuery<TElement>(Expression) 會轉換成型別 IOrderedQueryable<T> 並傳回。The result of calling CreateQuery<TElement>(Expression) is cast to type IOrderedQueryable<T> and returned.

執行表示呼叫的運算式樹狀架構所產生的查詢行為， ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>) 取決於參數類型的實作為 source 。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>>) depends on the implementation of the type of the source parameter. 預期的行為是它會 source 根據在 keySelector 的每個專案上叫用所取得的索引鍵，執行專案的次要排序 source 。The expected behavior is that it performs a secondary sort of the elements of source based on the key obtained by invoking keySelector on each element of source. 所有先前建立的排序次序都會保留下來。All previously established sort orders are preserved.