I'm DouBa

1. Add the Mono repository to your system
   The package repository hosts the packages you need, add it with the following commands in a root shell.
   Note:the packages should work on newer CentOS/RHEL versions too but we only test the ones listed below.
   CentOS/RHEL 8(x86_64)

rpm --import "https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF" 
su -c 'curl https://download.mono-project.com/repo/centos8-stable.repo | tee /etc/yum.repos.d/mono-centos8-stable.repo' 

CentOS/RHEL 7(x86_64)

rpm --import "https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF" 
su -c 'curl https://download.mono-project.com/repo/centos7-stable.repo | tee /etc/yum.repos.d/mono-centos7-stable.repo' 

CentOS/RHEL 6(x86_64, i686)

rpm --import "https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF" 
su -c 'curl https://download.mono-project.com/repo/centos6-stable.repo | tee /etc/yum.repos.d/mono-centos6-stable.repo' 

2. Install Mono

yum install mono-devel

（The package mono-devel should be installed to compile code. ） 阅读全文