Integrating UnitOfWork and XPObjectSpace descendants into an XAF app

We've made some code changes for v17.2.6+ as well as created two articles for advanced XAF developers who may need the subject for some low-level tuning:

How to customize the UnitOfWork behavior in XPO-based XAF applications

How to customize the Object Space behavior in XPO-based XAF applications

Sub-classing is itself easy.  The most interesting part comes for the two popular security configurations: the Integrated  mode and the Middle-Tier Application Server. Thankfully, this is rarely required for complex or specific scenarios only.  Here are several customer tickets for your reference:

    How to map a property to a calculated database column (implement a read-only persistent property)
    xpo and sql server identity fields
    Using inherited UnitOfWork object
    XAF: Create CreateCustomObjectSpaceProvider with parameters from login window
    SecurityStrategyComplex: How to modify objects/properties in code when the user does not have the permission?

To learn more about low-level options to control how your application saves data and where, check out the How to customize the underlying database provider options and data access behavior in XAF.

Your feedback is needed!
Finally, I am just curious: if you search your entire solution in Visual Studio (Control+Shift+F) for any of the ": UnitOfWork", ": XPObjectSpace", ": XPObjectSpaceProvider" strings or their VB.NET equivalents (e.g., Inherits UnitOfWork), how many occurrences  would you have and for what? Please let me know in the comments!

XAF WinForms v17.2.6 - Beware of missing icons in inactive tabs after restoring the Tabbed MDI layout

I want to draw your attention to the T611846: DocumentManager - TabbedView does not show images for documents issue already fixed in the XtraBars Suite and which XAF WinForms Tabbed MDI users might encounter after upgrading to v17.2.6. The number of users who already hit this exceeded a certain threshold, and the known issues section in the What's New documentation or manual searching the Support Center may not help effectively discover it yourself. So, I am posting this here to widely inform those who have not yet upgraded their XAF/WinForms projects to v17.2.6.

You can also download a hotfix build from here.

Please accept sincerely apologies from our XAF and XtraBars teams for all the inconvenience here.

Diagnostic tool for Security System - YOUR FEEDBACK IS NEEDED!!!

Earlier we described the prototype of diagnostic tool. We created it to help a developer to understand why access to a certain object and its members is allowed or denied.  

  

We analyzed the feedback we got on this matter and provided the following improvements in v17.2.6:

 - To enable the security diagnostic tool, use the familiar EnableDiagnosticActions option.

 - You can select a type and a member you wish to analyze.

 - Results are presented in the XML format.

 - We provide more details on how the diagnostic tool calculates results.

 - There is a way to visualize criteria for easier analysis.

You can get more info about the tool from the KB article below:

                                     https://www.devexpress.com/kb=T589182.  

Your feedback is needed

Please test the tool and let us know whether it is useful in your development process and how you would change it. For instance, the more specific there are use cases of this tool where it was difficult to configure permissions for a user, the greater it is possible that we can arrive at technical solutions that will address them.

AccessViolationException at Microsoft.VisualStudio.Shell.Interop.IVsRegisterEditors.UnregisterEditor may occur in Visual Studio 2010, 2012

This sporadic design time error might go away in Visual Studio 2013, 2015, 2017 and newer.

Exception

Type: System.AccessViolationException
Message: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
StackTrace:
   Microsoft.VisualStudio.Shell.Interop.IVsRegisterEditors.UnregisterEditor(UInt32 dwCookie)
   Microsoft.VisualStudio.Shell.Package.Dispose(Boolean disposing)
   DevExpress.ExpressApp.Design.Core.XAFPackageV4.Dispose(Boolean disposing)
   Microsoft.VisualStudio.Shell.Package.Microsoft.VisualStudio.Shell.Interop.IVsPackage.Close()

We have been tracking this error for years from XAF users using https://logify.devexpress.com. We also received a few tickets, but could never replicate this behavior for debugging. Our attempts to log diagnostic information about this error did not help either. Well, it does not seem to relate to the DevExpress.ExpressApp.Design.Core.XAFPackageV4.Dispose method itself. There are also many non-XAF reports devoted to the same error, but different packages on the Web. https://www.google.com/search?q=Microsoft.VisualStudio.Shell.Interop.IVsRegisterEditors.UnregisterEditor+accessviolationexception

From the Logify stats, we know that this error occurs only with these two old Visual Studio versions. It seems that something got fixed in newer IDE versions. If you are on Visual Studio 2010 or 2012 and encountered this error at design time, consider upgrading your IDE - it's 2018 after all:-)

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.

Learning through reading the source code

I will start this post with the new Visual Studio 2017 function, which I hope will be helpful for XAF developers too. I have both RTM and Preview versions installed, but I am mostly using the latter one for testing. The new function I spotted in their change logs is called "View decompiled source definitions instead of metadata (C#)".

As you can guess from its name, it changes the very often used "Go To Definition" command (F12) so that it displays the actual code of a C# type or member who's source code is unavailable - very useful and convenient, IMHO. It is decompiled using ILSpy, the tool I have already been using for years as default program association for opening *.dll files -  partially the reason of why this news got my attention. This experimental feature is new in Visual Studio 2017 version 15.6 preview 2+ and it must be turned on explicitly using the Tools > Options  >  Text Editor > C# > Advanced > Enable navigation to decompiled sources menu item. 

Customization Forms and Model Editor Improvements - XAF v17.2.6

Customizing Views layout, e.g., making certain fields visible, changing their locations is something that XAF developers usually learn and appreciate from day one. That is because you can drastically change the UI of your app by just moving the mouse and without any coding and recompilation, also at runtime. 

The next maintenance release (v17.2.6) should come with a few minor improvements to the customization forms in DetailView, ListView and the Model Editor, which we hope will be welcomed by both developers and end-users as well.