The Early Access 3621 build comes with improvements for WinForms, WPF and more

Microsoft has announced the finalization of some features of version 4.8 of the .net Framework. Note that in the defined roadmap, the final version release of the .Net 4.8 Framework is scheduled for 2019. This date is still relevant. But here and there, the features that are validated by the Microsoft team can be submitted to developers for testing and possible returns. In this context, a new build, the 3621 Early Access in this case, was published for this version 4.8 of the .Net Framework. In this new preview, we have improvements in various areas including Windows Presentation Foundation (WPF) and Windows Forms (WinForms).


It is a package that allows projects that target low-level platforms to use certain infrastructure components so that projects that use specific packages can be built successfully. In this preview of the .Net 4.8 Framework, we have some corrections that have been made to the package.
System.Runtime.CompilerServices.RuntimeFeature.IsSupported has been corrected to correctly account for application compatibility settings for the portable PDB feature added in the .NET Framework 4.7.1;
A correction was made to one exception by analyzing Japanese dates whose number of the year exceeds the number of years in an epoch. The change of behavior will be perceptible only if one tries to analyze a date containing a certain time and a year whereas the year exceeds the last year of that time;
By default, high processes will not read HKCU for managed COM activation information.


ClickOnce is a component of the .Net Framework that allows you to deploy applications developed with WinForms and WPF. These applications can be on a web page behind a link, a network share space or on a CD, DVD, USB, etc. media. Regarding the improvements introduced in this new preview .Net Framework 4.8 Early Access build 3621, we have some points:

A fix has been made to ClickOnce's user interface dialogs for machines with high resolution and scaling that has been set to more than 100% for both new and old applications and that can reach the 300%;
The ClickOnce dialogs (startup screen, installation progress dialog box, maintenance dialog box, and update dialog box) that had accessibility issues have now been corrected;
A bug has been fixed in the right-to-left progress bar alignment in the start screen and in the ARA and HEB language download progress dialog for the ClickOnce user interface. In addition, the RTL layout in the dialog boxes has been corrected. Individual controls must be defined in the RTL layout because this property is not propagated. This property must now be set explicitly on the progress bar control.


CLR is a component of the .NET Framework virtual machine. For the improvements introduced in this version, we have:

LoadFrom (String, Byte [], AssemblyHashAlgorithm) works correctly with SHA2 algorithms;
Reduction of the AsyncLocal memory during the change of value;
Improved timeouts in multiple synchronization primitives to improve Intel Skylake performance and newer microarchitectures;
Several problems were detected when incorrect values ​​were sent to EventListeners. This includes invalid activity IDs on start and stop events and incorrect EventLevel values. These problems have been fixed;
A potential crash occurred during concurrent calls to a new dynamic method. This has also been corrected.

Windows Forms

Windows Forms or WinForms is a library of the .NET Framework that contains a set of useful tools for designing graphical user interfaces. In this build 3621, several improvements and bugfixes have been added. We among other things:

Activated labels are now rendered using high contrast text color when high contrast mode is enabled. This change is effective in recompiled applications to target the .NET 4.8 Framework;
A bug was discovered about scaling the maximize / collapse button of the new child form on HDPI devices because the image property is set to not scale. This has been corrected;
Accessibility for DateTimePicker control has been improved. In order for the application to benefit from these changes, the application must be recompiled to target the .NET Framework 4.8 or the application must explicitly accept all accessibility application context changes in the app.config file;
A new fix has been added for the text of application and application directory tags that was truncated on localized operating systems. The text of the labels is now displayed in full;
A new UIA behavior for numeric and top-down domain controls has been added: numeric and top-down domain controls without tags (custom UIA name) are announced by the Narrator as "spinners". This change is effective in applications that have been recompiled to target the .NET 4.8 Framework;
A new UIA behavior for the CheckedListBox control has been added: an empty CheckedListBox control now has a focus rectangle drawn for a first virtual element when the control has focus. This change is also effective in applications that have been recompiled to target the .NET Framework 4.8.


Windows Presentation Foundation is a presentation system that can be used to generate standalone and browser-hosted Windows client applications. It integrates the XAML descriptive language that allows to use it in a way close to an HTML page for developers. Several fixes have been made in this preview of the .Net 4.8 Framework. These include:

A correction to a memory leak that occurs when deleting data items from their parent collections when UIAutomation is present;
When the Items collection contained duplicate objects, the ItemsControl virtualization crashed during scrolling. This problem has been corrected ;
An issue that sometimes resulted in incorrect loading of XAML browser applications (XBAP) targeting the .NET 3.5 Framework using .NET 4.x runtime was also fixed;
WPF applications running in high contrast mode had selection visuals that were difficult to see on DataGridCells. This new preview of the .Net 4.8 Framework corrects this problem.
Several other improvements and bugfixes have been added in this build 3621 of the Early Access program of the .Net 4.8 Framework. In addition, although these features have been approved by the Microsoft team, it is recommended that they not be used in production at this time. Returns are expected by the maintainers of the Framework in case of discovery of bugs.

Source : Microsoft

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