Queryable.ThenBy Queryable.ThenBy Queryable.ThenBy Queryable.ThenBy Method

使用指定的比較子，依遞增順序執行序列中項目的後續排序作業。Performs a subsequent ordering of the elements in a sequence in ascending order by using a specified comparer.

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);

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

例外狀況

備註

這個方法至少有一個類型Expression<TDelegate>的參數, 其類型引數是其中一個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, 它會編譯成Expression<TDelegate>。For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

方法會產生, 其代表以ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>)結構化泛型方法的方式呼叫本身。 MethodCallExpression ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>)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MethodCallExpression將傳遞CreateQuery<TElement>(Expression)至由Provider source參數IQueryProvider的屬性所表示之的方法。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CreateQuery<TElement>(Expression)的結果會轉換成類型IOrderedQueryable<T> , 並傳回。The result of calling CreateQuery<TElement>(Expression) is cast to type IOrderedQueryable<T> and returned.

因執行代表呼叫ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>)之運算式樹狀架構而產生的查詢行為, 取決於source參數類型的實作為。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. 預期的行為是根據在的source source每個專案keySelector上叫用所取得的索引鍵, 來執行的專案的次要排序。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。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.

依據索引鍵，按遞增順序執行序列中項目的後續排序作業。Performs a subsequent ordering of the elements in a sequence in ascending order according to a key.

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

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排序。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Expression<TDelegate>的參數, 其類型引數是其中一個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, 它會編譯成Expression<TDelegate>。For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

方法會產生, 其代表以ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>)結構化泛型方法的方式呼叫本身。 MethodCallExpression ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>)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MethodCallExpression將傳遞CreateQuery<TElement>(Expression)至由Provider source參數IQueryProvider的屬性所表示之的方法。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CreateQuery<TElement>(Expression)的結果會轉換成類型IOrderedQueryable<T> , 並傳回。The result of calling CreateQuery<TElement>(Expression) is cast to type IOrderedQueryable<T> and returned.

因執行代表呼叫ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>)之運算式樹狀架構而產生的查詢行為, 取決於source參數類型的實作為。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. 預期的行為是根據在的source source每個專案keySelector上叫用所取得的索引鍵, 來執行的專案的次要排序。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。All previously established sort orders are preserved.