ExecuteQueryAsync(EntityManager,IEntityQuery,Action<EntityQueryOperation>,Object) Method

Execute a query asynchronously.

Syntax

Visual Basic
C#

'Declaration
 
<ExtensionAttribute()>
Public Overloads Shared Function ExecuteQueryAsync( _
   ByVal em As EntityManager, _
   ByVal query As IEntityQuery, _
   ByVal userCallback As Action(Of EntityQueryOperation), _
   Optional ByVal userState As Object _
) As EntityQueryOperation

'Usage
 
Dim em As EntityManager
Dim query As IEntityQuery
Dim userCallback As Action(Of EntityQueryOperation)
Dim userState As Object
Dim value As EntityQueryOperation
 
value = EntityManagerAsyncExtensions.ExecuteQueryAsync(em, query, userCallback, userState)

[Extension()]
public static EntityQueryOperation ExecuteQueryAsync( 
   EntityManager em,
   IEntityQuery query,
   Action<EntityQueryOperation> userCallback,
   object userState
)

Parameters

em: EntityManager
query: The IdeaBlade.EntityModel.IEntityQuery to execute
userCallback: Callback invoked when the query completes
userState: Token to identify the query upon completion

Remarks

Provide a userCallback if you want to be notified when the operation completes. The query results will be returned in the IdeaBlade.EntityModel.EntityQueriedEventArgs passed to the userCallback. Use the userState to uniquely identify this call. You can cancel a pending asynchronous call using IdeaBlade.EntityModel.BaseOperation<TEventArgs,TOp>.Cancel method.

Example

private void SampleAsynchQuery() {
  DomainModelEntityManager mgr = new DomainModelEntityManager();

  // Build a query and ask mgr to run it asynchronously.
  var query = mgr.Customers.Where(c => c.CompanyName.StartsWith("C"));
  int token = 1;
  mgr.ExecuteQueryAsync(query, AsyncQueryCompleted, token);
}

void AsyncQueryCompleted(EntityQueryOperation<Customer> e) {
  if (e.Error != null) {
    System.Diagnostics.Debug.WriteLine(e.Error.Message);
    return;
  }
  System.Diagnostics.Debug.WriteLine("queryid = " + e.UserState.ToString());
  System.Diagnostics.Debug.WriteLine("customers retrieved = " + e.Results.Count().ToString());
}

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

EntityManagerAsyncExtensions Class
EntityManagerAsyncExtensions Members
Overload List