Support for .NET 5 about opendnp3

[jadamcrain]

I am not a .NET authority, by any means, perhaps @emgre can weigh in since he's looked at this for our new libraries that are based on PInvoke instead of C++/CLI. In those projects we are targeting .NET Standard which gives broad framework interop.

Here's a guide a about targeting different frameworks with C++/CLI:

https://docs.microsoft.com/en-us/dotnet/core/porting/cpp-cli

It seems that we cannot target .NET Standard, so we might have to build a multi-target package in the next release.

[andrepf]

For me, it would be enough if next release multi-targets Full Framework/.NET 5. Thanks!

[emgre]

@andrepf I quickly tried it this morning. With this feature that was merged in CMake 3.17, it is possible to define the target property DOTNET_TARGET_FRAMEWORK to net5.0 and it should work. The changes would be here

opendnp3/dotnet/CLRInterface/CMakeLists.txt

Line 138 in 132f2fd

set_property(TARGET DNP3CLRInterface PROPERTY VS_DOTNET_TARGET_FRAMEWORK_VERSION ${DNP3_DOTNET_FRAMEWORK_VERSION})

and here

opendnp3/dotnet/CLRAdapter/CMakeLists.txt

Line 55 in 132f2fd

set_property(TARGET DNP3CLRAdapter PROPERTY VS_DOTNET_TARGET_FRAMEWORK_VERSION ${DNP3_DOTNET_FRAMEWORK_VERSION})

and properly setting the DNP3_DOTNET_FRAMEWORK_VERSION CMake variable to net5.0.

I tried compiling it that way but I ran on issues with my installation of Visual Studio (I had to update it to get .NET 5.0 and it failed).