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

執行中使用指定的比較子，依遞增順序的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

這個方法有至少一個參數的型別Expression<TDelegate>的類型引數是其中一個Func<T,TResult>型別。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，您可以傳遞 lambda 運算式中，將會編譯為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>)方法會產生MethodCallExpression，表示呼叫ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>)本身做為建構的泛型方法。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. 它接著會傳遞MethodCallExpression要CreateQuery<TElement>(Expression)方法IQueryProvider由Provider屬性source參數。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)轉換為類型IOrderedQueryable<T>後傳回。The result of calling CreateQuery<TElement>(Expression) is cast to type IOrderedQueryable<T> and returned.

因執行運算式樹狀架構表示呼叫的查詢行為ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>)之型別的實作而定source參數。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，它會執行次要排序之項目的source藉由叫用的索引鍵為基礎keySelector各項目上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會保留。All previously established sort orders are preserved. comparer參數用來比較索引鍵的值。The comparer parameter is used to compare key values.

執行以遞增順序依據索引鍵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>>)執行次要排序序列中的項目。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

這個方法有至少一個參數的型別Expression<TDelegate>的類型引數是其中一個Func<T,TResult>型別。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，您可以傳遞 lambda 運算式中，將會編譯為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>>)方法會產生MethodCallExpression，表示呼叫ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>)本身做為建構的泛型方法。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. 它接著會傳遞MethodCallExpression要CreateQuery<TElement>(Expression)方法IQueryProvider由Provider屬性source參數。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)轉換為類型IOrderedQueryable<T>後傳回。The result of calling CreateQuery<TElement>(Expression) is cast to type IOrderedQueryable<T> and returned.

因執行運算式樹狀架構表示呼叫的查詢行為ThenBy<TSource,TKey>(IOrderedQueryable<TSource>, Expression<Func<TSource,TKey>>)之型別的實作而定source參數。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，它會執行次要排序之項目的source藉由叫用的索引鍵為基礎keySelector各項目上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會保留。All previously established sort orders are preserved.