How to access and manipulate a custom ASP.NET user control from a Controller in a Module project

We have updated our How to: Show a Custom Data-Bound Control in an XAF View (ASP.NET) tutorial with more information on how to pass external data to custom Web user controls. 

Previously, our customers had the following difficulties with this task:

- In which project to create web user controls. By default, ASP.NET suggests doing this in the YourSolution.Web project. Adding an *.ASCX control into the YourSolutionName.Module.Web project led to errors.

- How to deal with circular references when attempting to reference the YourSolution.Web project from a Controller defined in the YourSolutionName.Module.Web project.

- How to pass an IObjectSpace, XafApplication or current View object to a custom user control.

A common way to resolve such a dependency (unrelated to XAF itself) is to define an interface within your class library (a XAF module project) and implement it by using your custom user control.

Usability change for SingleChoiceAction with a single visible sub-item - YOUR FEEDBACK IS NEEDED!!!

We have incorporated the usability improvement from my past post in v18.1 by default. It affects SingleChoiceAction with ShowItemsOnlyClick = False and ItemType = ItemIsOperation  and should improve UX for the majority of our users. We also want to enable the same behavior in an upcoming minor update (e.g., v17.2.6 or next). Our team would appreciate your feedback to help us decide on the latter.

Questions/Risks

While this behavior is always desired for the New & Clone Actions, because their meaning is clear from the context, certain custom and built-in Actions like Show In Report, Change State may be affected when they keep only a single sub-item. Examples:

17.2.5 and older versions:

18.1 (and 17.2.6+, if the majority likes it):

Notice that we've replaced a dropdown/triangle glyph with a simple button. We believe that this visual change is still not breaking (and thus is acceptable for a minor version), and it all is more logical than it was before. Before, when ShowItemsOnClick = False, you could still press the SingleChoiceAction's button blindly, i.e., without expanding its items using the triangle glyph. To help you avoid mistakes, the button is now displayed in the ChoiceActionItem's tooltip. You can also control the default Action item behavior using the DefaultItemMode property. If you do not like the new behavior, you can always set ShowItemsOnClick = True in the Model Editor.

Question: Are you OK to have this new behavior as default in v17.2.6+ too? 

Please answer with +1 or -1 with comments in this post. If you need to test your real apps live before making a decision, I can provide you with v17.2 or v18.1 hotfix builds. Thanks for your help in advance.

UPDATE:
Thanks to everyone! With v17.2.6, this behavior is enabled by default.

No Visual Studio designers for generic ViewController versions

XAF Controllers are technically descendants of the System.ComponentModel.Component class, primarily to be smoothly integrated with the Visual Studio design time features. The standard Component designer does not support generic classes due to a Visual Studio limitation: https://stackoverflow.com/questions/6877217/can-visual-studio-designer-show-classes-inheriting-generic-types 

This is a Microsoft functionality and we cannot do much about it on our side. So, if you have a class like this, and try to double click it or use the Enter key for it in the Solution Explorer, you will receive this error, which is expected here:

This has always caused support calls to us from day one and still causes them today. Check out this support article to learn more about this situation and our previous recommendations.

Starting with v17.2.6, we have removed the visual designer association from the base ViewController<ViewType> and ObjectViewController<ViewType, ObjectType> classes - they will always be opened directly in the Code Editor now. This should work fine in Visual Studio 2015, 2017 and newer versions. This does not work for Visual Studio 2013 and older versions and we decided not to investigate this further, because of the very low usage rate of these IDEs nowadays.

We believe that this new behavior is most expected here and really hope that it will not cause new questions😀. Originally, generic View Controllers were specially designed for users who prefer to do everything manually and want to have a more elegant and compact code. So, opening the Code Editor for such classes is naturally expected. Taking this opportunity, we also improved our online documentation to further promote generic View Controllers, since most of our Support Center answers, demos and docs use this concise code approach anyway.

My team and I are looking forward to hear from you on what you think of the new behavior.

How to drag & drop file attachments from Outlook messages into ListView or DetailView with FileData objects

I would like to promote a KB article, which may be interesting for users of our File Attachments module and Microsoft Outlook, because we introduced a few changes to XAF codebase (v17.2.5+) to make their integration simpler for the following customer's scenario (attaching files directly from Outlook messages):

>>I am using the FileAttachmentBase to add files to a class in my project. Drag/Drop works great if I want to add a file from Windows Explorer. I want to be able to drag an attachment from Outlook and drop it into my application in the same way.

https://www.devexpress.com/kb=S19805

Accessing real persistent objects through the SelectedObjects and CurrentObject properties of View and Action's event arguments when DataAccessMode = DataView or InstantFeedback

The View.CurrentObject and View.SelectedObjects properties return XafDataViewRecord objects instead of original business objects when the View operates in DataView mode (and XafInstantFeedbackRecord - in InstantFeedback mode). To get a real object, you can use the View.ObjectSpace.GetObject(obj) method.

I just wanted to remind you of this specificity and detail currently recommended solution strategies:

https://www.devexpress.com/kb=T584572

According to our current figures for support traffic in this regard (for one year of the InstantFeedback mode existence and more than two years of the DataView mode existence), this is not a big deal for our users - I located less than seven support requests in total. Probably, this is due to the fact that our learning materials already describe this or due to the fact that the DataView and InstantFeedback modes are used rarely, only when ListView contains a lot of records. Here I must also emphasize that this behavior exists in the first place because returning real objects by default may prevent you from getting all the benefits of these data access modes... So, we implemented the current design on purpose.

Should you have difficulties with these features and aforementioned solutions or can foresee better options, my team and I are happy to listen. For instance, one of the alternative solutions I saw in a couple places was the implementation of the auxiliary GetRealSelectedObjects/GetRealCurrentObject methods.

Survey (~1min): Default location of the Reset View Settings Action - YOUR FEEDBACK IS NEEDED!!!

This command is provided by the standard ResetViewSettingsController and resets all the user customizations of the View's model. It may be helpful when your client customized a lot and was stuck getting things to normal. Due to this scenario the command is available in the main menu toolbar or ribbon by default (+additionally duplicated in context menu in WinForms).

However, we wanted to hear the XAF community thoughts on this default design after receiving several user requests in this regard (examples: one, two, three). As of now, we have no easy capability to know real usages and customizations of XAF Actions in end client apps, so we would greatly appreciate it if you participate in this and coming surveys. Thanks for your help in advance.

https://dxsurvey.com/published?id=45965fae-dfc7-48ac-af26-aee17d2c3ec4

In fact, we already asked our user preferences when this feature was in development, but did not receive much feedback back then to hide this command from the main menu by default.

Controller creation performance optimization v17.2 Preview - YOUR FEEDBACK IS NEEDED!

Starting with version 17.2, we've further optimized the process of creating Controllers that should positively affect forms loading performance and thus overall end user experience, especially in very complex detail forms.  In addition to List Property Editors (learn more about v17.1 improvements in this regard), Detail, Object and Lookup Property Editors, DashboardViewItem and popup windows created in a special way were supported. We are publishing this KB article prior to the 17.2 release to collect early user feedback and improve the overall stability:

https://www.devexpress.com/kb=T535119

If you are an active v17.1 subscriber and want to test this feature with your real world applications on a virtual machine (or another suitable test environment) prior to the official release, please leave a comment to this KB article or rather create a separate private ticket, so that we can verify your account and provide you with a v17.2 preview installation privately.

We would appreciate your thoughts and feedback once you've had the opportunity to try this new feature in your upgraded v17.2 project. Please report any issues and suggestions in our Support Center. Thanks for your help in advance!

Web - How to preserve the FullTextSearch Action filter after opening details for a record and returning back to ListView

I want to repost an interesting ASP.NET WebForms scenario and a solution for it I provided to a customer yesterday. Watch this video to see how this works:

If you are interested in having something like this, check out this Support Center thread for a relatively simple Controller.

The Frame.GetController method may return null when the XafApplication.OptimizedControllersCreation property is set to True

With XAF v17.1, Solution Wizard sets the XafApplication.OptimizedControllersCreation property to True for newly created XAF projects (existing projects will not be affected). 

To avoid possible null reference exceptions in nested List Views, always check if the Frame.GetController<ControllerType> method result is not null when the OptimizedControllersCreation property is true. The latter option is required to get faster loading of DetailView when it contains a lot of nested ListView items (learn more...).

Our online documentation was already updated to describe this optimization specificity and add these null-checks everywhere; e.g., check theses examples: one, two. KB articles, Code Examples and popular Support Center tickets are not yet updated, but we hope to do this with time as well. Should you find missing checks in our learning materials, please contact us.

Faster opening of DetailView with many visible ListPropertyEditors (not in tabs) in complex XAF solutions with lots of Controllers - YOUR FEEDBACK IS NEEDED!

What is behind this optimization? 

With XAF v17.1, we have introduced some optimizations with regard to Controller creation for a Frame inside ListPropertyEditor, which is usually used to represent associated detail collections. That main idea behind this optimization is filtering out certain Controllers by their TargetXXX properties and not creating them at all .On our test machines, which are often multi-core i7 monsters with 16GB ROM, the loading time after this optimization was cut on 0.2-0.3 seconds or on 20% depending on the view configuration (we expect double time on your real client machines with budget i3-i5 or lower CPUs).

Specially for early testing 1-2 months prior to the official release, we have introduced a feature toggle in the current XAF v16.2 and showing this feature there as a preview. 

When should I be interested in this?

You can skip this post if you do not have many custom Controllers in your apps, because the effect of our optimization will unlikely be noticeable in your case.

You must definitely read further if you have hundreds of own Controllers + use third-party modules like Xafari/eXpand with many custom Controllers in them.

Another condition is DetailView layout configuration, which I would rather clarify with a couple screenshots:

If you have the A configuration, you will NOT benefit much from the optimization we introduced, because there is only one visible ListPropertyEditor in the active tab that affect the overall parent DetailView opening. 

If you have the B configuration, you have several visible ListPropertyEditors that require creating Controllers for their nested Frames immediately with the opening of the parent DetailView and thus slow things down a little. You can either turn our optimization on or consider hiding these ListPropertyEditors behind the tabbed group.

How do I test this right now?

Please download the latest  DevExpressComponents-16.2.5.17082.exe build and set the new XafApplication.OptimizedControllersCreation property to True in the constructor of your XafApplication descendant located in the YourSolutionName.Wxx/WxxApplication.xx file (or in the YourSolutionName.Win/Program.xx or YourSolutionName.Web/Global.asax.xx files), e.g. as follows:

namespace MainDemo.Win {

public partial class MainDemoWinApplication : WinApplication {

public MainDemoWinApplication() {

InitializeComponent();

                        this.OptimizedControllersCreation = true;

}

New ways to customize the New Action's items list in XAF v16.2.5 - YOUR FEEDBACK IS NEEDED!!!

Changing the way how the New Action's items list is populated is quite an often task. The default behavior when the current types and all its descendants are added may be inappropriate in large XAF applications with a complex business objects inheritance hierarchy.

That is why we have decided to provide more built-in modes of populating this list. The available modes are listed in the DevExpress.ExpressApp.SystemModule.NewObjectActionItemListMode enumeration.

Value	Description
Default	The current type and all of its descendant types are added.
ExcludeBaseType	All descendants of the current type are added. The current type itself is excluded.
LastDescendantsOnly	Only the last types in the inheritance hierarchy of the current type are added.

Preview of toast notifications using a platform-agnostic method in XAF v16.2.5 - YOUR FEEDBACK IS NEEDED!!!

I am still forcing myself to go to sleep after watching an unreal football drama in Barcelona, so I am writing this short blog post at night.
Besides Visual Studio 2017 official support, XAF v16.2.5 delivers a small gem, which I cannot hide from you too long. Remember that this is an early preview of the functionality we hope to officially release by v17.1 and which is have polished in the coming 2-3 months. So, your feedback is welcome, as always!

Typical usage

Let's modify the platform-agnostic Controller from our demo (C:\Users\Public\Documents\DevExpress Demos 16.2\Components\eXpressApp Framework\SimpleProjectManager\CS\SimpleProjectManager.Module\Controllers\ProjectTaskController.cs) by adding the Application.ShowViewStrategy.ShowMessage call at the end of the Execute event handler:
...
            markCompletedAction.Execute += (s, e) => {
                IObjectSpace viewDataContext = View.ObjectSpace;
                foreach(ProjectTask task in e.SelectedObjects) {
                    task.EndDate = DateTime.Now;
                    task.Status = ProjectTaskStatus.Completed;
                    viewDataContext.SetModified(task); // Mark the changed object as 'dirty' (only required if data properties do not provide change notifications).
                }
                viewDataContext.CommitChanges();
                //viewDataContext.Refresh(); // Optionally update the UI in accordance with the latest data changes.
                Application.ShowViewStrategy.ShowMessage(string.Format("{0} task(s) have been completed!", e.SelectedObjects.Count), InformationType.Success, 4000, InformationPosition.Top);
            };
...
Now, let's start the Windows and Web apps, select a few uncompleted tasks in the ProjectTask ListView and execute the Done! command from the menu.

Result in the UI for various platforms

Web

A nice notification window is managed using the dxToast widget (invoked via the  DevExpress.ui.notify method) from our DevExtreme HTML5/JavaScript library:

How to change an Application Model option globally or for multiple nodes

I have recently updated one of the articles on the subject in our support knowledge base and wanted to test-drive this content with you: https://www.devexpress.com/kb=T271022

Since the Application Model basically represents a skeleton of the application UI, based on which visual controls for supported platforms are created at runtime, updates to various options in the source UI metadata (both at design time and runtime) can be a good and often platform-agnostic alternative to customizing underlying controls directly in Controllers or other UI entities (examples: one, two, three). The most difficult thing is to perform this update at the right moment or using the right event in the View life cycle!

Even though this may sound like a quite an advanced topic, this is one of the core concepts for our framework, which I recommend you get familiar with.

Your feedback is welcome, as always!

We also hope to use this KB as a base for future updates of the online documentation at  Concepts > Application Model  for easier discoverability, so your early feedback on the main methods I described is welcome. In particular, I would greatly appreciate your comments on whether you experienced the scenarios needed runtime Application Model updates and exactly which techniques you used (e.g., #2.1, 2.2 or all ).

How to customize the New Object Action with a single item to display a simple button instead of a dropdown in WinForms

UPDATE:
See the latest post on this matter at Usability change for SingleChoiceAction with a single sub-item - YOUR FEEDBACK IS NEEDED!!!
-----------------------------------------------------------------------
I would like to promote an updated/simplified v16.2 solution for this task after introduction of the ActionBase > CustomizeControl event. To remind you the context, let me quote myself from the https://www.devexpress.com/kb=Q497985 thread:

"XAF allows defining whether a SingleChoiceAction click should show a dropdown or execute an action item immediately using the ShowItemsOnClick and DefaultItemMode  properties. You can easily change these properties based on the number of the New action items. However, a triangle glyph is always shown by default. The SingleChoiceAction does not currently provide built-in means for replacing a dropdown with a simple button either. Currently, to improve user experience with such configurations, you can customize the underlying bar item in the YourSolutionName.Module.Win project.

You can use the following controller to hide a drop-down list from the NewObjectAction in case it contains only one element:

using DevExpress.ExpressApp;
using DevExpress.ExpressApp.Actions;
using DevExpress.ExpressApp.Win.SystemModule;
using DevExpress.XtraBars;
...
namespace YourSolutionName.Module.Win.Controllers {
    public class CustomizeNewActionController : WindowController {
        BarButtonItem newActionBarButtonItem;
        protected override void OnFrameAssigned() {
            base.OnFrameAssigned();
            WinNewObjectViewController newObjectViewController = Frame.GetController<WinNewObjectViewController>();
            SingleChoiceAction newObjectAction = newObjectViewController.NewObjectAction;
            newObjectAction.CustomizeControl += NewObjectAction_CustomizeControl;
            newObjectAction.ItemsChanged += NewObjectAction_ItemsChanged;
        }
        private void NewObjectAction_ItemsChanged(object sender, ItemsChangedEventArgs e) {
            if(newActionBarButtonItem != null) {
                SingleChoiceAction newObjectAction = (SingleChoiceAction)sender;
                int choicesCount = newObjectAction.Items.Count;
                if(choicesCount == 1) {
                    newActionBarButtonItem.ButtonStyle = BarButtonStyle.Default;
                }
            }
        }
        private void NewObjectAction_CustomizeControl(object sender, CustomizeControlEventArgs e) {
            newActionBarButtonItem = e.Control as BarButtonItem;
        }
    }
}

Here are screenshots showing the results in the application UI before and after this customization.

Before

After

Also, you can use the same approach with the CloneObjectAction (it is a part of the CloneObjectViewController). Refer to the following documentation articles to learn more about this solution:
    Concepts > Extend Functionality > Built-in Controllers and Actions 
    Concepts > Extend Functionality > Customize Controllers and Actions 
    Task-Based Help > How to: Customize Action Controls
    DevExpress.XtraBars > BarButtonItem > ButtonStyle 
    DevExpress.XtraBars > BarButtonItem > ActAsDropDown 


For older versions
Check out the How to display a dropdown without a triangle glyph for a SingleChoiceAction ticket for code examples."

How to refresh View appearance after making changes to the Application Model in code

With XAF v16.2.4, you can apply Application Model changes to a View without recreating it. To do this, save the Frame's View to a variable and then unlink it from the Frame by passing null to the SetView method. After that, make the required changes to the model, call the LoadModel method with the false parameter and then set the saved View back to the Frame using the SetView method. Here is the generic code illustrating this pattern:

View view = Frame.View;

if(Frame.SetView(null, true, null, false)) {

    // Make required changes with the model here. 

    // ... 

    view.LoadModel(false);

    Frame.SetView(view);

}

You can find a full ViewController code for accomplishing the two most popular WinForms scenarios benefiting from this capability in the https://www.devexpress.com/kb=S173664 article (switching a ListView editor type and MasterDetailMode). 
This video also illustrates how it works in the application UI in action. 

Leave a comment if this is something you are going to try right now!

As always, please report any issues using the https://www.devexpress.com/ask service. Thanks in advance!

A WinForms example for collapsing/expanding layout groups and persisting their state

As you probably know, the New Web UI was recently enhanced with built-in options for this scenario. Today, I have updated the https://www.devexpress.com/kb=S135134 thread with a WinForms solution:

Please don't hesitate to write to us about each use case scenario that requires additional code to adjust the layout controls to better meet your business needs. My team and I will be more than happy to research them and see how to manage this situation better at the XAF or DevExpress component level. For instance, here we are thinking about providing platform-agnostic Application Model extensions for managing this task for Windows and the Web.

Implementing State Machines at the Business Object vs Controller levels - YOUR FEEDBACK IS NEEDED!!!

I wanted to seriously question the current approach for declaring state machines in code using the StateMachine<T> class and IState/IStateMachineProvider interfaces (Predefined State Transitions Created in Code) and hear what you think of it in general. The main reasons behind this interest are the limitations this originally implemented approach has compared to other available solutions and hence associated support costs.

"Yet Another Controller"© 

In fact, in certain scenarios, creating a custom Controller with the SingleChoiceAction Action or a set of SimpleAction Actions can be simpler and more straightforward than defining a coded State Machine at a domain level. To give you a concrete example of such an alternative solution, check out this Controller that eventually does the same thing as the code in the original documentation article above, but with old-good SimpleAction objects manipulated on View and other suitable events. You can find another example with a SingleChoiceAction in this test project (it's from this SC ticket, so process it with the Project Converter tool first). Even though the alternative Controller-based approach requires more code, it allows you to provide a more granular control over created states and their visual representations. It is cleaner and easier to understand/extend for other business requirements, because it is your own code that uses only the basic XAF APIs.

Implications of using the questioned approach
Contrary to that, the questioned approach is really a bit shorter with the help of 'state', 'transition' and 'state appearance' abstractions defined near your business class, but everything has its own trade offs.

How to map Actions to a certain RibbonPage and RibbonGroup via the Application Model

This is my second post about advanced ribbon menu customizations in XAF WinForms apps. This time I want to repost two possible solutions for the aforementioned task after reviewing and updating the code of one good (and never old - Hi, Noxe!:-)) customer recently. This work was done after an interview about my Simplifying customization of Action controls - YOUR FEEDBACK IS NEEDED! post. Take a look at it if you haven't yet. 

Long story short, refer to the https://www.devexpress.com/kb=S134617 ticket and find two possible Controller implementations. Even though the first one (RibbonFromModelWithEventController.cs) requires more code to implement, I like it more, because it does not require you to create an Action Container node manually in the Model Editor. With the first one, you just specify the TargetRibbonPage and TargetRibbonGroup properties for a required Action under the ActionDesign node and you are done:

In any case, I suggest you play with both implementations and watch the attached video to determine what is more suitable for you. I look forward to hearing from you in the comments section or in the Support Center, as always.

I do not want to focus much on the Controller code itself, just want to note that there we extended the standard IModelAction interface corresponding to the ActionDesign | Action node and then handled these new options in our code. This is one of my favorite Application Model features, which is also truly loved by our customers. In fact, everything you see in our framework is built using the same simple principle: you have certain UI metadata or settings store and have some Controllers in modules that create/customize visual controls accordingly. To learn more about this, refer to the Concepts > Application Model > Extend and Customize the Application Model in Code article in our online documentation. This is a really cool feature and it can help you create a more reusable code.

How to place all nested View commands into the main ribbon and activate them based on the selected layout tab

My next two posts will be devoted to advanced ribbon menu customizations in WinForms, which become much easier to implement with the introduction of the new Ribbon and Standard templates (WinApplication.UseOldTemplates = False) back in v14.2 and also API changes in the recent XAF versions.

The current post is about mapping ALL Actions from the nested Frame toolbar into the main ribbon menu by creating a separate page. It is planned that when you activate a certain nested ListView within a layout tab, its related View commands will be activated in a separate ribbon page as well (context-dependent commands). This somewhat exotic approach was requested a few times by different customers and is likely dictated by users who have a habit of using only the main ribbon menu, i.e., without moving the mouse to the bottom context.

The two pictures showing how it was before and after making necessary code changes + a video showing everything in action are worth a thousand words in communicating this effect in the real app.

Context-dependent Actions in ribbon

How to find and deactivate a problematic Controller "on the fly" via an application UI for troubleshooting purposes

I wanted to repost a troubleshooting tip our old XAFer and MVP Dave Hesketh has kindly provided in the Support Center today. BTW, Dave also provides XAF training and custom development services, based out of Ontario, Canada, so this may be not the last thing you would want to learn from him and his website. 

So, let me focus on the problem and solution he described at https://www.devexpress.com/kb=T433881 and also also quickly show it all in action with one of the XAF demos:

"I have come across a few scenarios where something seems to be slowing down an XAF solution and it is tough to determine where the issue exists. This can then lead to hours of tearing out controllers to try and determine if one is problematic.

To make this process easier, I have created a module that you can add to an XAF solution to Enable and Disable controllers on the fly.

Once you add this module to your solution, you will find the "Show Controller Settings" action in the Tools menu. In the dialog that appears, you can enable or disable any controllers you wish, or click the "Disable Custom Controllers" to disable non-DevExpress controllers (A good starting place). 

Please note: Once you enable or disable controllers, you must re-open a view for the change to take effect. This solution has been tested on existing Win Applications only."

I remember a couple of similar requests from other guys, and indeed, this dynamic exclusion of Controllers without recompiling and restarting the whole app can be helpful when researching certain complex problems like performance or behavioral/visual side effects. For many other cases, the built-in Diagnostic Action, application log files, and performance profilers would suffice pretty well. 

Anyway, let's check how to use Dave's module with our MainDemo.Win app. Consider the following steps: