Thursday, August 9, 2018

Can I Port My Windows Desktop Application to .NET Core? Find Out and Prepare Today!

Did you know that soon you will be able to build and run your WPF (and UWP & WinForms) applications against .NET Core?

Desktop Packs

At the Microsoft Build conference in May, it was announced that the .NET team was working on some Windows-only "Desktop Packs" that could be installed on top of .NET Core v3.0. These packs would include:

  • WPF
  • WinForms
  • UWP
  • Entity Framework v6

This will bring the benefits of .NET Core to desktop client applications running on Windows. In my opinion, the biggest benefits of porting your desktop app to .NET Core will be significant performance gains and full access to Windows 10 APIs.

Obviously, in most cases, it won't be as simple as changing a project property and rebuilding your app. Project files will need to be upgraded to .NET Core format, and some legacy APIs will not be available, even in the Desktop Pack packages. This week, it has become more clear exactly which APIs will not be available in .NET Core 3.0 with Desktop Packs.

Portability Analyzer

On Wednesday, the .NET team released a Portability Analyzer tool to scan your .NET desktop applications and determine how ready they are to upgrade to .NET Core 3.0. The tool will scan your .NET binaries and dependencies and produce an Excel report (PortabilityReport.xlsx) with several tabs:

Portability Summary - This sheet contains a list of the assemblies scanned, their current .NET version target, and the % compatibility they are expected to have with .NET Core 3.0.

Details - This sheet provides details on exactly which target type and member are currently used by one of your assemblies that is not compatible with .NET Core 3.0. There is a column for Recommended Changes, but none of my incompatibilities had any recommendations.

Missing assemblies - If your assemblies reference any other assemblies which could not be resolved by the tool, they will be listed here.

My Thoughts

I ran the tool on a large application with a mix of WinForms and WPF windows. The folder contains over 900 DLLs. My thoughts:

First, I was pleasantly surprised at how fast the tool ran its analysis. It completed scanning this large application in less than a minute. I was expecting to go get a cup of coffee and a snack while it ran.

Second, the team has really included a lot of desktop APIs in these packs. I was not expecting so many of my DLLs to report at 100% compatible.

Third, many of the incompatible APIs are somewhat expected. Here are a few that came back in the report here:

  • Microsoft.VisualBasic.* - If you have VB apps, and use APIs in this namespace, expect a lot of lines to appear in your report.
  • System.Drawing.Design.* and System.Drawing.ImageConverter - Much of the System.Drawing namespaces was ported to .NET Core, but not everything. If you're doing anything advanced or uncommon, you'll probably find some issues here.
  • Things that are less common in modern development like System.Xml.XmlDataDocument, System.Runtime.Remoting.Messaging, and System.Activator.GetObject.

Console Tool

If you would prefer to run the analyzer against several applications and product individual reports for each, you can use a console analyzer with a batch file or PowerShell script instead. That version is available here, and instructions for using it are in the .NET team's post about the Portability Analyzer.


Go get your app ready for .NET Core 3.0 today! Your users will thank you later.