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QueryInterceptorAttribute Class

The QueryInterceptorAttribute on a method annotates it as a query interceptor on the specified entity set.

System.Object
  System.Attribute
    System.Data.Services.QueryInterceptorAttribute

Namespace:  System.Data.Services
Assembly:  System.Data.Services (in System.Data.Services.dll)

[AttributeUsageAttribute(AttributeTargets.Method, AllowMultiple = true, Inherited = true)]
public sealed class QueryInterceptorAttribute : Attribute

The QueryInterceptorAttribute type exposes the following members.

  NameDescription
Public methodQueryInterceptorAttributeInitializes a new instance of the QueryInterceptorAttribute class for the entity set specified by the entitySetName parameter.
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  NameDescription
Public propertyEntitySetNameGets the name of the entity set that contains the entity to which the interceptor applies.
Public propertyTypeIdWhen implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)
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  NameDescription
Public methodEqualsInfrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeReturns the hash code for this instance. (Inherited from Attribute.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodIsDefaultAttributeWhen overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
Public methodMatchWhen overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
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  NameDescription
Explicit interface implemetationPrivate method_Attribute.GetIDsOfNamesMaps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoRetrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoCountRetrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.InvokeProvides access to properties and methods exposed by an object. (Inherited from Attribute.)
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Entity set-level authorization and validation is implemented by methods annotated with the QueryInterceptorAttribute. WCF Data Servicess do not implement security policies but instead provide the infrastructure required for service developers to write their own security rules and business validation.

Entity set access control and validation is enabled through query operations by using query composition. To control entity-based access, implement a method-per-entity set according to the following rules:

The method must have public scope and be annotated with the QueryInterceptorAttribute, taking the name of a entity set as a parameter.

The method must accept no parameters.

The method must return an expression of type Expression<Func<T, bool>> that is the filter to be composed for the entity set.

The following example controls access to the Customers entity set. Each Customer can only see Orders associated with that Customer.

[QueryInterceptor("Orders")]
public Expression<Func<Order, bool>> FilterOrders() 
{
    return o => o.Customer.Name == /* Current principal name. */;
} 
 
// Insures that the user accessing the customer(s) has the appropriate
// rights as defined in the QueryRules object to access the customer
// resource(s).
 
[QueryInterceptor ("Customers")]
public Expression<Func<Customer, bool>> FilterCustomers() 
{
  return c => c.Name == /* Current principal name. */ &&
              this.CurrentDataSource.QueryRules.Contains(
                rule => rule.Name == c.Name &&
                        rule.CustomerAllowedToQuery == true
              );
}

.NET Framework

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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