Is there any method to display pop up message like MessageBox.Show in .NET core?
Update:
Yes. .NetCore 3.0+ supports WPF/Windows Forms
As John Dyer noted in comments,
VB users can use this for a message box: https://learn.microsoft.com/en-us/dotnet/api/system.windows.messagebox?view=netcore-3.1
Original answer 2017:
No. .NET Core is focused on web, Messagebox is a winforms thing. And there is no winforms support in .NET Core.
A more-or-less official answer on "Why is there no Microsoft.UI.WinForms .Net Core package"
My team (the Microsoft .NET team) is focused on .NET Core as a cloud and web framework. We know that folks would like us to build additional application types for .NET Core. For now, we're remaining focused. Many other developers want us to stay focused on what we've started with .NET Core and that's our intention.