XafApplication.ObjectSpaceProvider Property

Provides access to the application’s Object Space Provider.

Namespace: DevExpress.ExpressApp

Assembly: DevExpress.ExpressApp.v23.2.dll

NuGet Package: DevExpress.ExpressApp

Declaration

C#

[Browsable(false)]
public IObjectSpaceProvider ObjectSpaceProvider { get; }

VB.NET

<Browsable(False)>
Public ReadOnly Property ObjectSpaceProvider As IObjectSpaceProvider

Property Value

Type	Description
IObjectSpaceProvider	An instance of the class that implements the IObjectSpaceProvider interface.

Remarks

XAF uses an Object Space Provider to create Object Spaces. It is a class that implements members of the IObjectSpaceProvider interface. The following Object Space Provider types are supplied with XAF:

• XPObjectSpaceProvider - Creates the XPObjectSpace Object Space that manipulates data using the XPO ORM system.
• EFCoreObjectSpaceProvider<TDbContext> - Creates the EFCoreObjectSpace Object Space that manipulates data using the Entity Framework ORM system.
• SecuredObjectSpaceProvider - Creates the SecuredXPObjectSpace Object Space that takes the current user’s security permissions into account.
• SecuredEFCoreObjectSpaceProvider<TDbContext> - Creates the SecuredEFCoreObjectSpace Object Space that takes the current user’s security permissions into account.
• NonPersistentObjectSpaceProvider - Creates the NonPersistentObjectSpace Object Space that manipulates non-persistent object instances.

By default, XPObjectSpaceProvider is created because the WinForms and ASP.NET Web Forms application project templates override the CreateDefaultObjectSpaceProvider method of the corresponding XafApplication descendant in the following manner:

C#

public partial class MainDemoWinApplication : WinApplication {
//...
    protected override void CreateDefaultObjectSpaceProvider(
        CreateCustomObjectSpaceProviderEventArgs args) {
        args.ObjectSpaceProvider = new XPObjectSpaceProvider(args.ConnectionString, args.Connection);
    }
}

VB.NET

Partial Public Class MainDemoWinApplication
    Inherits WinApplication
    '...
    Protected Overrides Sub CreateDefaultObjectSpaceProvider( _
    ByVal args As CreateCustomObjectSpaceProviderEventArgs)
        args.ObjectSpaceProvider = _
        New XPObjectSpaceProvider(args.ConnectionString, args.Connection)
    End Sub
End Class

The CreateDefaultObjectSpaceProvider method is called when creating an Object Space Provider during the application’s setup if a particular Object Space Provider is not passed as a parameter in the Setup method call. So, check that an Object Space Provider is not passed in your Setup method call, as in the following code:

C#

static class Program {
    // ...
    public static void Main() {
        // ...
        MainDemoWinApplication application = new MainDemoWinApplication();
        // ...
        application.Setup();
        application.Start();
        // ...
    }
}

VB.NET

Friend Class Program
    ' ...
    Public Shared Sub Main()
        ' ...
        Dim _application As MainDemoWinApplication = 
        New MainDemoWinApplication()
        ' ...
        _application.Setup()
        _application.Start()
       ' ...
    End Sub
End Class

To create an Object Space Provider, the application uses the connection string specified using the XafApplication.ConnectionString property. If you need to specify a custom connection string or create an Object Space Provider of another type, implement a custom override of the CreateDefaultObjectSpaceProvider method. Alternatively, you can handle the XafApplication.CreateCustomObjectSpaceProvider event to pass a custom Object Space Provider.

Note

XAF uses the first registered Object Space Provider for the following purposes:

• To get XafApplication.ObjectSpaceProvider and XafApplication.ConnectionString property values.
• To pass this Provider as the CustomCheckCompatibilityEventArgs ObjectSpaceProvider argument.
• To update an application.

Ensure that NonPersistentObjectSpaceProvider is not the first registered Provider in your application.

Note that in applications with the Application Builder, you need to use the Application Builder’s ObjectSpaceProviders property to register Object Space Providers instead of the XafApplication.CreateDefaultObjectSpaceProvider method or XafApplication.CreateCustomObjectSpaceProvider event to register Object Space Providers. Refer to the following help topic for more information on how to do this: Integrate Application Builders into Existing Applications.

We strongly recommend this because the use of the XafApplication.CreateDefaultObjectSpaceProvider method and XafApplication.CreateCustomObjectSpaceProvider event conflicts with IObjectSpaceFactory and IObjectSpaceProviderFactory service usage.

This technique also improves performance of your application because the application instance is not created in this case.