eXpress App Framework Team

May 2016 - Posts

  • XAF - UX Improvements for Design Time Templates, Windows and Web UI (Coming soon in v16.1)

    Design-time enhancements

    With our upcoming release, all XAF templates will be available from the DX Template Gallery (look for the DevExpress v16.1 Template Gallery item in the standard Add New Item... dialog or see the "Add DevExpress Item" context menu item for your projects in Solution Explorer):

    Additionally, we've provided shortcuts for the most recently used (MRU) item templates to the Add DevExpress Item... menu - invoked for XAF projects under the Solution Explorer:

    Notice that there is a new Non-Persistent Object item template that allows you to create non-persistent classes with ease (it contains all the required boilerplate code and example implementations of the INotifyPropertyChanged, IXafEntityObject, IObjectSpaceLink interfaces). Please review my earlier blog post to learn on more improvements with regard to managing non-persistent objects in standard XAF forms. See the Changes to Visual Studio Item Templates in XAF v16.1 KB article for more details.

    WinForms SDI: Outlook-Style Navigation Integration

    For those of you targeting Windows, XAF's integration of DevExpress WinForms Outlook-Style navigation controls and OfficeNavigationBar is now better than ever.

    The OfficeNavigationBar can be displayed in non-compact mode, as in the screenshot above, or in the compact mode (enabled by default) demonstrated below:

    You can always switch between compact and non-compact modes via the Navigation Options dialog ().

    Each navigation link at the bottom of the OfficeNavigationBar panel corresponds to the root navigation group defined under the NavigationItems node.

    Clicking on these group items can be include animations managed by our TransitionManager component  where the SlideFadeTransition type is used by default (view a full-size GIF without losing quality HERE):

    This new feature is enabled only in SDI mode (UIType = SingleWindowSDI) with the ribbon menu (FormStyle=Ribbon) when the new RootGroupStyle property is set to OutlookSimple or OutlookAnimated. You can initialize these configurations in code or via the Model Editor:

    For a cleaner UI and better end-user experience, the DockPanel previously hosting the NavBarControl was also removed. The NavBarControl is now positioned directly in the form template, which also helped us remove unnecessary borders.

    The expand/collapse functions of the removed dock panel are now natively managed by the NavBarControl and the two new buttons added into the status bar. The "Normal View" button expands the NavBarControl while pressing the "Reading View" button collapses the NavBarControl.

    SVG icons support in ASP.NET

    In XAF ASP.NET applications, SVG images are now supported, which improves your website's appearance on displays with high pixel density (resolution).

    If you're adding custom images as per this documentation article, note that image display size is determined by the svg element's viewBox attribute. Also, SVG icons are not grayed out automatically for disabled Actions. You should manually add a disabled variant of an SVG icon with the _Disabled suffix (e.g., MyIcon_Disabled.svg).

    Our UX designers also started to redraw standard XAF images, but this is still in works. You can easily view already updated images in the Model Editor's image picker:

    Our future plans include completing this image collection and to introduce this same capability for XAF's WinForms UI.

    Faster rendering and other performance optimizations for popular Web UI scenarios

    In short, the core idea for all these performance improvements in XAF ASP.NET WebForms apps is that under certain circumstances, we intentionally suppress creation and rendering of current web page controls, disable unnecessary data-binding operations, reduce the number of requests to the server and perform updates on the client side where possible. This allows us to produce a web app that behaves faster and is more responsive, which is essential for hand-held devices (e.g., tablets, smart phones). Desktop web browser users will also benefit from these changes, especially in scenarios involving popup windows.

    Since several thousand of our unit and complex functional tests have passed, these optimizations are turned on by default in XAF v16.1, so that everyone can benefit from them. For backward compatibility or any unhandled issues in your custom code that might occur due to these optimizations, we also provided various static options in the DevExpress.ExpressApp.Web.WebApplication.OptimizationSettings class allowing you to turn this feature off completely (or partially). I've described these options and scenarios in the following KB Article: 

    Your feedback is needed!

    As always, my team and I look forward to hearing your thoughts on each of these improvements in comments to this blog or via the service.

  • XAF - Reports and Security System Enhancements (Coming soon in v16.1)

    This post is devoted to several improvements for the two key features of any serious line-of-business application - reporting and security. As you might expect from a mature application framework, DevExpress XAF ships with reusable ReportsV2 and Security modules designed to simplify the integration of the DevExpress Reporting Platform and role-based authorization features (actually much more than this!) for Windows, Web and Mobile platforms.

    Let's take a look and see what's inside the upcoming major release for reports and security.

    Grid Based Reporting in WinForms Applications

    XAF now supports the built-in printing/export capabilities of the DevExpress Grid and thus allows you to create a report from any grid-based List View. The report's layout is autocreated (and is based on grid columns, appearance and filter settings) when you click the "New Report" command in the Export menu.

    Technically, this is done by handling the ExportController.ExportActionItemsCreated event from the WinGridReportExportController and adding a New report item to the ExportController.ExportAction.

    The New report item invokes the Report Designer. The current grid layout is automatically converted to a report layout. You can learn more about report generation rules in our Advanced Grid Printing and Exporting topic.

    If you click Save, the report is saved to the application database, together with other user-defined reports.

    Allow/Deny Modifier for Security Permissions (Beta)

    With XAF's Security System, your application administrators can now allow access to all data within the application for a specific role and simultaneously deny access to a few data types or members. Alternatively, an end-user can deny access to all data for a role and only allow access to a strict list of objects or members. Both approaches make it easy to allow/deny data access across a broad range of use-case scenarios. To use this feature, choose Allow/Deny Permission Policy on the Choose Security page of the Solution Wizard.

    As a result, special types of security users and roles will be used in your application - PermissionPolicyUser and PermissionPolicyRole. Entity Framework and XPO versions of these classes are declared in the Business Class Library. The primary difference with SecuritySystemUser and SecuritySystemRole classes (which were previously used by default and are now used for the Deny All policy) is that the role object exposes the PermissionPolicy property:

    With this property, you can assign "deny all", "read only all" or "allow all" default permission policies for each role. This allows you to create very complex and flexible security configurations.

    For each operation, you can explicitly specify the Allow or Deny modifier or leave it blank.

    If the modifier is not specified, the permission is determined by the role's policy type. Note that policy has the lowest priority and is in play only when permissions are not explicitly specified.

    Dynamic Permissions for Associated Objects

    To allow users to modify objects used in associations (one-to-many and many-to-many), you should grant access to the properties on both sides of the association, because linking and unlinking operations always lead to the modification of both properties. XAF's Security System now simplifies this task by detecting associations and configuring required permissions automatically.

    Required permissions are granted dynamically each time an associated object is requested when the ServerPermissionRequestProcessor.UseAutoAssociationPermission or ServerPermissionPolicyRequestProcessor.UseAutoAssociationPermission static field is set to true. The former field is considered for the Deny All policy, and the latter - for the Allow/Deny policy (see the Allow/Deny Modifier for Security Permissions section above). The SecuritySystem.IsGranted request for a member is processed as follows in this mode.

    • The default security request is processed for a given member. If permission is granted, the result of this request is returned.
    • If permission is not granted at the previous step and the current member is an association (see IMemberInfo.IsAssociation), the request is processed for the associated member. The result of this additional request is returned.
    • If permission is not granted at the first step, and the current member is not an association, Security System checks if the member type is aggregated to another type. If owner type is found, a permission for the corresponding aggregated collection is requested and returned.

    The SecuritySystem.IsGranted request for a type or object is processed as follows.

    • The default security request is processed for the given type. If type permission is granted, the result is returned.
    • If type permission is not granted at the previous step, Security System checks if the type is aggregated to another type. If the owner type is found, a permission for the corresponding aggregated collection is requested and returned.
    • The requests for the Navigate operation are not processed using associations.

    Simply stated, you configure permissions on one side of the one-to-many or many-to-many association, and the same configuration is automatically applied on the other side. If this does not fit your requirements, you can always configure permissions explicitly.

  • XAF - Startup Performance, Application Model and Non-Persistent Objects Enhancements (Coming soon in v16.1)

    In my opinion, XAF's Application Model (defined as a set of application settings or UI skeleton) is the second most important XAF feature (first being automatic database and CRUD forms generation based on your ORM data model).

    Because of its importance, we consistently strive to improve the Application Model and in our upcoming release, we focused our energies on improving startup application performance and general usability for XAF developers.

    Application Model Caching

    With v16.1, you can speed up WinForms application startup using the EnableModelCache property. When set to true, Application Model content is cached to a file when the application is first launched and recovered on subsequent runs. This property works in a production environment when the debugger is not attached (see Debugger.IsAttached). By default, EnableModelCache is set to false. To change this property value, add the following code to the Program.cs (Program.vb) file, before the Setup method is called: winApplication.EnableModelCache = true;

    As a result of these settings, Nodes Generators and Generator Updaters will be executed and the Model.Cache.xafml cache file will be created only when the application is started for the first time. Note that initial startup can take more time than normal, however, the time taken by subsequent startups will be reduced, because the Application Model content will be recovered from the cache. The cache is recreated when application module version is incremented. 

    By default, the Model.Cache.xafml file is located in the application folder. You can change its path using one of the following methods:
    1. override the GetModelCacheFileLocationPath method in XafApplication descendant;
    2. use the ModelCacheLocation key in the configuration file (App.config).

    The Model.Cache.xafml file name is specified by the ModelStoreBase.ModelCacheDefaultName constant. If your application is localized, separate cache files are created for each language (e.g. Model.Cache_de.xafml).


    Frequently Asked Questions

    Q: How is this different from the existing ModelAssembly.dll-based cache?
    A: Unlike the existing ModelAssembly file-based cache (which is technically an assembly providing Application Model object implementation based on the IModelXXX interfaces), the new model cache file contains the entire model structure in XAFML format.

    Q: Is this cached file an equivalent of merging of the platform agnostic model and WinForms/ASP.NET models?  Does this include user modifications?
    A: No, this Model.Cache.xafml only contains an unchangeable Application Model layer. Administrative (Model.XAFML) and user-specific (e.g. Model.User.XAFML) model differences are not cached (they are meant to be modified once the app is deployed).

    Q: Is generation of this cache file somehow connected with database schema changes?
    A: No.

    Q: Can this cached file be supplied with the installer?
    A: Absolutely. You can generate this file by running your app without the debugger attached and then copy it into your installation program. This manual process may be unnecessary in many cases because the cache file will still be automatically generated after the released application is executed for the first time.

    Q: What about this feature for ASP.NET?
    A: By default, the EnableModelCache property has no effect on an ASP.NET application since a shared application model is usually generated once for all web clients. If you wish, you can manually activate the creation of this cache file by overriding the GetModelCacheFileLocationPath method of your WebApplication descendant.

    Application Model Database Storage Enhancements

    As you know, XAF apps can store user-defined application customizations (layouts, selected skin, etc.) in an application database with the use of the ModelDifferenceDbStore class introduced several releases ago. In this release, we've enhanced functionality in the following ways:

    • Design-time customizations are now always loaded from the Model.xafml file stored in the file system to simplify debugging.
      In other words, for administrative model differences we have returned to the schema we used prior to introduction of ModelDifferenceDbStore. Only user-specific model differences are loaded from the database by default. When required, you can uncomment the XafApplication.CreateCustomModelDifferenceStore event subscription manually. Note that Model.xafml file content will be loaded to the database once the application starts. Further changes to this file will be ignored if the database record already exists for shared model differences. To reload settings from Model.xafml, enable the administrative UI and use the Import Shared Model Difference Action (or delete the Shared Model Difference record and restart).

    • ModelDifferenceDbStore can now be used when the Security System is disabled.
      Currently, if the Security System is enabled, the SecuritySystem.CurrentUserId value is used as the identifier.  The System.Security.Principal.WindowsIdentity.GetCurrent().Name value is used as a user identifier (passed to the IModelDifference.UserId property) when the Security System is disabled. So, you can enable ModelDifferenceDbStore for WinForms applications with the disabled Security System using the approach described here. However, we do not recommended that you enable ModelDifferenceDbStore for unsecured ASP.NET applications because the UserID will be the same for all users. Shared model differences are supported for both WinForms and ASP.NET when the Security System is disabled. 

    • XML settings are now validated before being persisted.
      This is a small usability improvement to simplify error debugging when using ModelDifferenceDbStore and when the administrative UI for editing model differences is enabled in the application as described here. Application administrators will not be able to save invalid XML, e.g. with unclosed tags.


    Non-Persistent Objects Enhancements

    We continue incorporating non-persistent objects support implemented in our most recent releases with the help of the NonPersistentObjectSpace and NonPersistentObjectSpaceProvider classes.

    With this release, you can display persistent objects in a non-persistent object view with much less code. This is possible with the help of the AdditionalObjectSpaces property in the NonPersistentObjectSpace class. It is best to illustrate this improvement with a short code snippet:

    [DomainComponent, DefaultClassOptions]
    public class NonPersistentObject {
        // ... 
        public string Name { get; set; }
        public Person Owner { get; set; }
    public class AdditionalPersonObjectSpaceController : WindowController {
        private IObjectSpace additionalObjectSpace;
        protected override void OnActivated() {
            Application.ObjectSpaceCreated += Application_ObjectSpaceCreated;
            additionalObjectSpace = Application.CreateObjectSpace(typeof(Person));
    private void Application_ObjectSpaceCreated(Object sender, ObjectSpaceCreatedEventArgs e) {
            if (e.ObjectSpace is NonPersistentObjectSpace) {

    Once XAF v16.1 is released, refer to the "How to: Show Persistent Objects in a Non-Persistent Object's View" article in the online documentation for a full tutorial and additional explanations. Also notice the new ORM-agnostic DevExpress.ExpressApp.Data.Key attribute we introduced to mark unique key properties of an object type.


    Another improvement involves showing a non-persistent Detail View: Separately (e.g., from a navigation control or in a popup window) or Embedded (inside a DashboardView item). With XAF v16.1, you can handle the new ObjectByKeyGetting event of the NonPersistentObjectSpace class to provide a non-persistent object instance manually. As an example, consider a scenario when a navigation item pointing to a non-persistent class DetailView was added under the NavigationItems node and its ObjectKey parameter was specified in the Model Editor as shown below:


    You can now add the following Controller to handle this scenario:

    public class NonPersistentObjectsController : WindowController {
        protected override void OnActivated() {
            Application.ObjectSpaceCreated += Application_ObjectSpaceCreated;
        private void Application_ObjectSpaceCreated(object sender, ObjectSpaceCreatedEventArgs e) {
            NonPersistentObjectSpace nonPersistentObjectSpace = e.ObjectSpace as NonPersistentObjectSpace;
            if(nonPersistentObjectSpace != null) {
                nonPersistentObjectSpace.ObjectByKeyGetting += nonPersistentObjectSpace_ObjectByKeyGetting;
        private void nonPersistentObjectSpace_ObjectByKeyGetting(object sender, ObjectByKeyGettingEventArgs e) {
            if(e.ObjectType.IsAssignableFrom(typeof(NonPersistentObject))) {
                if(((int)e.Key) == 138) {
                    NonPersistentObject obj138 = new NonPersistentObject();
                    obj138.Name = "Sample Object";
                    e.Object = obj138;

    If you want to create a non-persistent object automatically for each Detail View, you do not need to specify an ObjectKey in the Model Editor. Leave the ObjectKey value empty and create the following View Controller, which will create a non-persistent object

    public class NonPersistentObjectActivatorController : ViewController<DetailView> {
        protected override void OnActivated() {
            if(ObjectSpace is NonPersistentObjectSpace) {
                View.CurrentObject = View.ObjectTypeInfo.CreateInstance();

    On a final note, let me add that custom calculated fields are now supported as well. In other words, you can define custom fields  for non-persistent types in the Model Editor with the Expression attribute like NonPersistentProperty1 + NonPersistentProperty2.

    Several types have changed their host assemblies without changes in namespaces

    This is just a formal notification as this change should not be "breaking" or affect you at all in the majority of cases. Refer to the Several types have been moved to the DevExpress.Persistent.Base and DevExpress.Persistent.BaseImpl assemblies from the Charts, ConditionalAppearance, KPI and StateMachine modules in XAF v16.1 KB Article for more details.


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