ObjectQuery<T>.Except(ObjectQuery<T>) Metodo

Definizione

Limita i risultati della query escludendo quelli basati sui risultati di un'altra query di oggetto.Limits the query results by excluding results based on the results of another object query.

public:
 System::Data::Objects::ObjectQuery<T> ^ Except(System::Data::Objects::ObjectQuery<T> ^ query);
public System.Data.Objects.ObjectQuery<T> Except (System.Data.Objects.ObjectQuery<T> query);
member this.Except : System.Data.Objects.ObjectQuery<'T> -> System.Data.Objects.ObjectQuery<'T>
Public Function Except (query As ObjectQuery(Of T)) As ObjectQuery(Of T)

Parametri

query
ObjectQuery<T>

Oggetto ObjectQuery<T> che rappresenta i risultati da escludere dalla query.An ObjectQuery<T> that represents the results to exclude from the query.

Restituisce

Nuova istanza di ObjectQuery<T> equivalente all'istanza originale con l'operatore EXCEPT applicato in base al parametro query.A new ObjectQuery<T> instance that is equivalent to the original instance with EXCEPT applied based on the specified query.

Eccezioni

Il parametro query è null oppure una stringa vuota.The query parameter is null or an empty string.

Esempi

Questo esempio è basato sul modello Sales di AdventureWorks.This example is based on the AdventureWorks Sales Model. Nell'esempio viene utilizzato il metodo Except per creare un nuovo oggetto ObjectQuery<T>, quindi vengono scorsi i risultati della nuova query.The example uses Except method to create a new ObjectQuery<T> object and then iterates through the result of the new query.

int productID = 900;
using (AdventureWorksEntities context =
    new AdventureWorksEntities())
{
    string queryString = @"SELECT VALUE product 
        FROM AdventureWorksEntities.Products AS product";

    ObjectQuery<Product> productQuery =
        new ObjectQuery<Product>(queryString,
            context, MergeOption.NoTracking);

    string queryString2 = @"SELECT VALUE product 
        FROM AdventureWorksEntities.Products 
        AS product WHERE product.ProductID < @productID";

    ObjectQuery<Product> productQuery2 =
        new ObjectQuery<Product>(queryString2,
            context, MergeOption.NoTracking);

    productQuery2.Parameters.Add(new ObjectParameter("productID", productID));

    ObjectQuery<Product> productQuery3 =
        productQuery.Except(productQuery2);

    Console.WriteLine("Result of Except");
    Console.WriteLine("------------------");

    // Iterate through the collection of Product items
    // after the Except method was called.
    foreach (Product result in productQuery3)
        Console.WriteLine("Product Name: {0}",
            result.ProductID);
}
Dim productID = 900
Using context As New AdventureWorksEntities()
    Dim queryString As String = "SELECT VALUE product FROM AdventureWorksEntities.Products AS product"
    Dim productQuery As New ObjectQuery(Of Product)(queryString, context, MergeOption.NoTracking)

    Dim queryString2 As String = "SELECT VALUE product FROM AdventureWorksEntities.Products " & _
        " AS product WHERE product.ProductID < @productID"
    Dim productQuery2 As New ObjectQuery(Of Product)(queryString2, context, MergeOption.NoTracking)
    productQuery2.Parameters.Add(New ObjectParameter("productID", productID))

    Dim productQuery3 As ObjectQuery(Of Product) = productQuery.Except(productQuery2)

    Console.WriteLine("Result of Except")
    Console.WriteLine("------------------")

    ' Iterate through the collection of Product items 
    ' after the Except method was called. 
    For Each result As Product In productQuery3
        Console.WriteLine("Product Name: {0}", result.ProductID)
    Next
End Using

Commenti

L'oggetto query fornito che definisce i risultati da escludere deve essere dello stesso tipo o di un tipo compatibile ObjectQuery<T>con.The supplied query that defines results to exclude must be of the same type or of a type that is compatible with the ObjectQuery<T>.

I parametri definiti nell'oggetto fornito query vengono uniti con i parametri definiti ObjectQuery<T> nell'istanza di.Parameters that are defined in the supplied query are merged with parameters that are defined in the ObjectQuery<T> instance. I parametri devono essere univoci nell'oggetto ObjectParameterCollection combinato.Parameters must be unique in the combined ObjectParameterCollection. Nella raccolta combinata non possono essere presenti due parametri con lo stesso nome.There cannot be two parameters in the combined collection with the same name. Per ulteriori informazioni, vedere Generatore di query Methods.For more information, see Query Builder Methods.

La query risultante eredita la connessione dall'istanza di ObjectQuery<T> su cui è stato chiamato il metodo Except.The resulting query inherits the connection from the ObjectQuery<T> instance on which Except was called.

Si applica a

Vedi anche