The file extension SLN is used by Microsoft's Visual Studio products. (eg Visual Studio 2010 Express) A SLN file is a Visual Studio Solution file and contains information about one or more projects.
Microsoft Visual Studio is a so-called IDE (Integrated Development Environment), ie integrated development environment and for various programming languages (C-Sharp, C ++, Visual Basic) available.
The SLN file is used to organize projects and project components. Since such a file contains only references and some settings data, you always need the project folder and the project file. This varies depending on the programming language used and can, for example, call .Csproj (for a C # project)
SLN files are indirectly downwards compatible. Visual Studio automatically detects and converts SLN files saved with older Visual Studio versions, making the whole project usable.
Unfortunately, the SLN file does not recognize the programming language used by the project. The only remedy here is the extension of the project file or a look into the project folder. Depending on the programming language used, you will find vb, c, cpp, or cs files there. To open a SLN file, Visual Studio must also be installed for the appropriate programming language.
Most often resolving problems with opening SLN files is very simple. Just install an appropriate program that supports such files. All of the listed programs support SLN files, but may vary in offered function and purpose. Some programs may be capable only of viewing contents of SLN files or offer file conversion options, but may not be capable of editing such files.
It is possible that although a compatible program has been installed on user’s system, it is not used by the system to open it. This may happen because no default application was associated with this type of files. To associate SLN files with given application, select "Open with" from drop-down menu (accessed by right-clicking on the file). Then select from the list the program or application you want to be used to open this type of file. If the MonoDevelop applications is not on the list, select "Browse" option in order to manually locate the directory where MonoDevelop has been installed.
Sometimes problems with opening SLN files may not lie with the application itself, but can arise due to other causes, such as: