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ObjectQuery<T> Constructor (String, ObjectContext)

Creates a new ObjectQuery<T> instance using the specified Entity SQL command as the initial query.

Namespace:  System.Data.Objects
Assembly:  System.Data.Entity (in System.Data.Entity.dll)
public ObjectQuery(
	string commandText,
	ObjectContext context
)

Parameters

commandText
Type: System.String

The Entity SQL query.

context
Type: System.Data.Objects.ObjectContext

The ObjectContext on which to execute the query.

An ObjectQuery<T> can be initialized in such a way that it represents a single scalar result and not a collection of scalar results. Some extension methods require collection results as input. In this case, an ArgumentException is thrown when one of these methods is called. For more information, see Object Queries (Entity Framework).

When your application generates Entity SQL queries at runtime, you should be aware of any command length limitations of the data source. Entity SQL does not enforce limitations on the length of the command text in queries.

The example in this topic is based on the Adventure Works Sales Model. The example shows how to construct an instance of the ObjectQuery<T> class.

using (AdventureWorksEntities advWorksContext =
    new AdventureWorksEntities())
{
    try
    {
        // Call the constructor with a query for products and the ObjectContext.
        ObjectQuery<Product> productQuery1 =
            new ObjectQuery<Product>("Product", advWorksContext);

        foreach (Product result in productQuery1)
            Console.WriteLine("Product Name: {0}", result.Name);

        string queryString =
            @"SELECT VALUE Product FROM AdventureWorksEntities.Product AS Product";

        // Call the constructor with the specified query and the ObjectContext.
        ObjectQuery<Product> productQuery2 =
            new ObjectQuery<Product>(queryString, advWorksContext);

        foreach (Product result in productQuery2)
            Console.WriteLine("Product Name: {0}", result.Name);

        // Call the constructor with the specified query, the ObjectContext,  
        // and the NoTracking merge option.
        ObjectQuery<Product> productQuery3 =
            new ObjectQuery<Product>(queryString, 
                advWorksContext, MergeOption.NoTracking);

        foreach (Product result in productQuery3)
            Console.WriteLine("Product Name: {0}", result.Name);
    }
    catch (EntitySqlException ex)
    {
        Console.WriteLine(ex.ToString());
    }
}

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

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

.NET Framework

Supported in: 3.5 SP1
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