Can you remove an Add-ed Type in PowerShell again?
I'm currently writing a library in C# and was using PowerShell to quickly test it on some occasions. However, this prevents me from re-building the project as PowerShell obviously still has the DLL open.
Is there a way of unloading the DLL again after adding it with Add-Type? The documentation doesn't seem to have clues on that and the obvious candidate would be Remove-Type (which doesn't exist – there is only one command anyway with Type as its noun). It gets cumbersome to close PowerShell and do all the stuff of navigating to the build directory and adding the type again each time I want to rebuild.
Answer
Like the others say, this is a .NET behavior. Assemblies loaded into an AppDomain cannot be unloaded. Only the AppDomain can be unloaded, and powershell uses a single appdomain. I blogged a bit about this some years ago:
When I test like this, I usually keep a shell open and use a nested shell to do tests. start powershell, cd to bin location then run "powershell" to start nested shell (new process.) "exit" to start over, and run "powershell" again.