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ObjectQuery<T>.Except Method

Limits the query results by excluding results based on the results of another object query.

Namespace:  System.Data.Objects
Assembly:  System.Data.Entity (in System.Data.Entity.dll)

public ObjectQuery<T> Except(
	ObjectQuery<T> query
)

Parameters

query
Type: System.Data.Objects.ObjectQuery<T>

An ObjectQuery<T> that represents the results to exclude from the query.

Return Value

Type: System.Data.Objects.ObjectQuery<T>
A new ObjectQuery<T> instance that is equivalent to the original instance with EXCEPT applied based on the specified query.

ExceptionCondition
ArgumentNullException

The query parameter is null or an empty string.

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>.

Parameters that are defined in the supplied query are merged with parameters that are defined in the ObjectQuery<T> instance. Parameters must be unique in the combined ObjectParameterCollection. There cannot be two parameters in the combined collection with the same name. For more information, see Query Builder Methods (Entity Framework).

The resulting query inherits the connection from the ObjectQuery<T> instance on which Except was called.

This example is based on the Adventure Works Sales Model. 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);
}

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5 SP1

.NET Framework Client Profile

Supported in: 4

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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