There are several different kinds of settings in MonoDevelop — Preferences, Policies and Project Options — and the distinction between them is not immediately clear. This post aims to provide an explanation of them and what they’re used for.
Preferences
Preferences control MonoDevelop’s behaviour and appearance, but do not directly affect projects’ code or output. This means that they are user-specific, and are stored in the user profile. Examples of preferences are the text editor’s colour scheme, whether the text editor shows line numbers, the font used for output pads, whether MonoDevelop jumps to errors after a build, and so on.
The Preferences dialog can be accessed from the MonoDevelop->Preferences menu item on Mac, the Tools->Options menu item on Windows, and the Edit->Preferences menu item on Linux. This is consistent with other applications on these platforms.
Project and Solution Options
Project Options are specific to projects, and affect how they’re built and run. This includes things like compiler options, the name of the output file, the arguments used when running the project, and so on. These options are stored in the project file, so other users will be able to build and run the project correctly. Where possible, they are mapped to the options used by Visual Studio and the MSBuild/xbuild command-line build tools.
The Project Options dialog can be accessed from the Project->{Project Name} Options menu item, or from the Options context menu item on the project in the solution pad, or by double-clicking on the project in the solution pad.
Some options are part of a project configuration. Projects can have multiple configurations, so by switching between them you can build different outputs. Configurations will be covered in a future post.
Solution Options are similar to Project Options, but for solutions. The Solution Options dialog can be accessed from the Project-> Solution Options menu item, or from the Options context menu item on the solution in the solution pad, or by double-clicking on the solution in the solution pad.
Policies
Policies are settings that affect how projects and code are formatted and organized, such as code formatting settings, naming conventions, and so on. In many other IDEs these settings are user-specific preferences, which means that different users working on the same project do things inconsistently, or have to change their preferences depending on which project they’re working. Policies ensure that these settings are consistent for different users working on a project, and make it easy to manage sets of policies across projects.
Because most policies are invariant across all projects within a solution, projects can be set to inherit the policy of their their parent solution or solution folder, and this is the default setting. This means that in most cases, policies only need to be edited on the solution, and these changes will be picked up by the projects. Policies settings panels are shown in the Project Options and Solution Options dialogs. They can be recognized by the “Policy” combo box at the top of the panel, which allows you to pick a policy to use, or set the item to inherit the policy from its parent. Alternatively, you can customize the settings, and the combo will show “Custom”.
When a solution is first created, or a solution without policies is saved, it will take its initial policies from the user’s default policies. From that point on, they are only stored in the solution and are not affected by changes in the user’s default policies, else solutions could not be shared between users and maintain consistent policies.
While Preferences and Project Options are familiar to users of many other IDEs, policies are something unique to MonoDevelop, and hence they sometimes cause confusion. Another post will explore the policies system in more detail.