Queryable.SkipWhile Queryable.SkipWhile Queryable.SkipWhile Queryable.SkipWhile Method

Definizione

Ignora gli elementi in una sequenza, purché una condizione specificata è true e quindi restituisce gli elementi rimanenti.Bypasses elements in a sequence as long as a specified condition is true and then returns the remaining elements.

Overload

SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>)

Ignora gli elementi in una sequenza, purché una condizione specificata è true e quindi restituisce gli elementi rimanenti.Bypasses elements in a sequence as long as a specified condition is true and then returns the remaining elements.

SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>)

Ignora gli elementi in una sequenza, purché una condizione specificata è true e quindi restituisce gli elementi rimanenti.Bypasses elements in a sequence as long as a specified condition is true and then returns the remaining elements. L'indice dell'elemento viene usato nella logica della funzione predicativa.The element's index is used in the logic of the predicate function.

SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>)

Ignora gli elementi in una sequenza, purché una condizione specificata è true e quindi restituisce gli elementi rimanenti.Bypasses elements in a sequence as long as a specified condition is true and then returns the remaining elements.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static System::Linq::IQueryable<TSource> ^ SkipWhile(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, bool> ^> ^ predicate);
public static System.Linq.IQueryable<TSource> SkipWhile<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,bool>> predicate);
static member SkipWhile : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, bool>> -> System.Linq.IQueryable<'Source>
<Extension()>
Public Function SkipWhile(Of TSource) (source As IQueryable(Of TSource), predicate As Expression(Of Func(Of TSource, Boolean))) As IQueryable(Of TSource)

Parametri di tipo

TSource

Tipo degli elementi di source.The type of the elements of source.

Parametri

source
IQueryable<TSource>

Un IQueryable<T> dal quale restituire elementi.An IQueryable<T> to return elements from.

predicate
Expression<Func<TSource,Boolean>>

Funzione per testare ogni elemento rispetto a una condizione.A function to test each element for a condition.

Restituisce

IQueryable<TSource>

Un' IQueryable<T> che contiene elementi dalla source a partire dal primo elemento nella serie lineare che non supera il test specificato da predicate.An IQueryable<T> that contains elements from source starting at the first element in the linear series that does not pass the test specified by predicate.

Eccezioni

source o predicate è null.source or predicate is null.

Esempi

Esempio di codice seguente viene illustrato come utilizzare SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) per ignorare gli elementi di una matrice, purché una condizione è true.The following code example demonstrates how to use SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) to skip elements of an array as long as a condition is true.

int[] grades = { 59, 82, 70, 56, 92, 98, 85 };

// Get all grades less than 80 by first
// sorting the grades in descending order and then
// taking all the grades after the first grade
// that is less than 80.
IEnumerable<int> lowerGrades =
    grades.AsQueryable()
    .OrderByDescending(grade => grade)
    .SkipWhile(grade => grade >= 80);

Console.WriteLine("All grades below 80:");
foreach (int grade in lowerGrades)
    Console.WriteLine(grade);

/*
    This code produces the following output:

    All grades below 80:
    70
    59
    56
*/

Dim grades() As Integer = {59, 82, 70, 56, 92, 98, 85}

' Get all grades less than 80 by first  sorting the grades 
' in descending order and then taking all the grades that 
' occur after the first grade that is less than 80.
Dim lowerGrades = grades.AsQueryable() _
    .OrderByDescending(Function(grade) grade) _
    .SkipWhile(Function(grade) grade >= 80)

Dim output As New System.Text.StringBuilder
output.AppendLine("All grades below 80:")
For Each grade As Integer In lowerGrades
    output.AppendLine(grade)
Next

' Display the output.
MsgBox(output.ToString())

' This code produces the following output:

' All grades below 80:
' 70
' 59
' 56

Commenti

Questo metodo ha almeno un parametro di tipo Expression<TDelegate> il cui argomento tipo è uno del Func<T,TResult> tipi.This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. Per questi parametri, è possibile passare in un'espressione lambda e verrà compilata per un Expression<TDelegate>.For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

Il SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) metodo genera un MethodCallExpression che rappresenta una chiamata SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) stesso come un metodo generico costruito.The SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) method generates a MethodCallExpression that represents calling SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) itself as a constructed generic method. Passa quindi il MethodCallExpression per il CreateQuery(Expression) metodo del IQueryProvider rappresentato dal Provider proprietà del source parametro.It then passes the MethodCallExpression to the CreateQuery(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

Il comportamento delle query che si verifica in seguito all'esecuzione di un albero delle espressioni che rappresenta una chiamata SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) dipende dall'implementazione del tipo del source parametro.The query behavior that occurs as a result of executing an expression tree that represents calling SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) depends on the implementation of the type of the source parameter. Il comportamento previsto è che venga applicata predicate a ogni elemento nel source fino a quando non viene trovato un elemento per cui predicate restituisce false.The expected behavior is that it applies predicate to each element in source until it finds an element for which predicate returns false. Tale elemento e tutti gli elementi rimanenti vengono restituiti.That element and all the remaining elements are returned.

SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>)

Ignora gli elementi in una sequenza, purché una condizione specificata è true e quindi restituisce gli elementi rimanenti.Bypasses elements in a sequence as long as a specified condition is true and then returns the remaining elements. L'indice dell'elemento viene usato nella logica della funzione predicativa.The element's index is used in the logic of the predicate function.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static System::Linq::IQueryable<TSource> ^ SkipWhile(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, int, bool> ^> ^ predicate);
public static System.Linq.IQueryable<TSource> SkipWhile<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,int,bool>> predicate);
static member SkipWhile : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, int, bool>> -> System.Linq.IQueryable<'Source>
<Extension()>
Public Function SkipWhile(Of TSource) (source As IQueryable(Of TSource), predicate As Expression(Of Func(Of TSource, Integer, Boolean))) As IQueryable(Of TSource)

Parametri di tipo

TSource

Tipo degli elementi di source.The type of the elements of source.

Parametri

source
IQueryable<TSource>

Un IQueryable<T> dal quale restituire elementi.An IQueryable<T> to return elements from.

predicate
Expression<Func<TSource,Int32,Boolean>>

Una funzione per testare ogni elemento una condizione. il secondo parametro di questa funzione rappresenta l'indice dell'elemento di origine.A function to test each element for a condition; the second parameter of this function represents the index of the source element.

Restituisce

IQueryable<TSource>

Un' IQueryable<T> che contiene elementi dalla source a partire dal primo elemento nella serie lineare che non supera il test specificato da predicate.An IQueryable<T> that contains elements from source starting at the first element in the linear series that does not pass the test specified by predicate.

Eccezioni

source o predicate è null.source or predicate is null.

Esempi

Esempio di codice seguente viene illustrato come utilizzare SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) per ignorare gli elementi della matrice fino a quando viene soddisfatta una condizione che dipende l'indice dell'elemento.The following code example demonstrates how to use SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) to skip elements of an array as long as a condition that depends on the element's index is true.

int[] amounts = { 5000, 2500, 9000, 8000, 
                    6500, 4000, 1500, 5500 };

// Skip over amounts in the array until the first amount
// that is less than or equal to the product of its
// index in the array and 1000. Take the remaining items.
IEnumerable<int> query =
    amounts.AsQueryable()
    .SkipWhile((amount, index) => amount > index * 1000);

foreach (int amount in query)
    Console.WriteLine(amount);

/*
    This code produces the following output:

    4000
    1500
    5500
*/

Dim amounts() As Integer = {5000, 2500, 9000, 8000, _
                    6500, 4000, 1500, 5500}

' Skip over amounts in the array until the first amount
' that is less than or equal to the product of its
' index in the array and 1000. Take the remaining items.
Dim query = amounts.AsQueryable() _
    .SkipWhile(Function(amount, index) amount > index * 1000)

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

' Display the output.
MsgBox(output.ToString())

' This code produces the following output:

' 4000
' 1500
' 5500

Commenti

Questo metodo ha almeno un parametro di tipo Expression<TDelegate> il cui argomento tipo è uno del Func<T,TResult> tipi.This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. Per questi parametri, è possibile passare in un'espressione lambda e verrà compilata per un Expression<TDelegate>.For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

Il SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) metodo genera un MethodCallExpression che rappresenta una chiamata SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) stesso come un metodo generico costruito.The SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) method generates a MethodCallExpression that represents calling SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) itself as a constructed generic method. Passa quindi il MethodCallExpression per il CreateQuery(Expression) metodo del IQueryProvider rappresentato dal Provider proprietà del source parametro.It then passes the MethodCallExpression to the CreateQuery(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

Il comportamento delle query che si verifica in seguito all'esecuzione di un albero delle espressioni che rappresenta una chiamata SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) dipende dall'implementazione del tipo del source parametro.The query behavior that occurs as a result of executing an expression tree that represents calling SkipWhile<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) depends on the implementation of the type of the source parameter. Il comportamento previsto è che venga applicata predicate a ogni elemento nel source fino a quando non viene trovato un elemento per cui predicate restituisce false.The expected behavior is that it applies predicate to each element in source until it finds an element for which predicate returns false. Tale elemento e tutti gli elementi rimanenti vengono restituiti.That element and all the remaining elements are returned. L'indice di ogni elemento di origine viene fornito come secondo argomento per predicate.The index of each source element is provided as the second argument to predicate.

Si applica a