Filter<TQuery>(TQuery,EntityQueryFilterCollection) Method

Append the specified filter collection to the query.

Syntax

Visual Basic
C#

'Declaration
 
<ExtensionAttribute()>
Public Overloads Shared Function Filter(Of TQuery As ITypedEntityQuery)( _
   ByVal query As TQuery, _
   ByVal filters As EntityQueryFilterCollection _
) As TQuery

'Usage
 
Dim query As TQuery
Dim filters As EntityQueryFilterCollection
Dim value As TQuery
 
value = EntityQueryExtensions.Filter(Of TQuery)(query, filters)

[Extension()]
public static TQuery Filter<TQuery>( 
   TQuery query,
   EntityQueryFilterCollection filters
)
where TQuery: ITypedEntityQuery

Parameters

query: Query to be appended to
filters: Collection of filters

Type Parameters

TQuery: Type queried

Return Value

A new query

Remarks

You can use an EntityQueryFilterCollection to filter different entity types in the query. The collection can also contain filters for types not currently in the query, and those filters will be ignored when the query is executed.

The Filter is most useful in appending to an existing query on the server prior to execution, where you cannot easily modify the query expression provided. The query may also be filtered on the client using the Querying event.

Note that Filter returns a new query with the filter(s) added; the original query is not modified.

Example

public void FilteringSample() {
  // Query for all customers.  A filter will be applied prior to execution.
  var mgr = new DomainModelEntityManager();
  mgr.Querying += new EventHandler<EntityQueryingEventArgs>(mgr_Querying);
  var list = mgr.Customers.ToList();
}

// Client-side filtering in the EM.Querying event handler
private void mgr_Querying(object sender, EntityQueryingEventArgs e) {
  EntityQueryFilterCollection clientFilters = new EntityQueryFilterCollection();
  clientFilters.AddFilter<Customer>(q => q.Where(c => c.Country == "UK"));
  e.Query = e.Query.Filter(clientFilters);
}

Requirements

Target Platforms: 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

Reference

EntityQueryExtensions Class
EntityQueryExtensions Members
Overload List