.net – MSBuild 15 NuGet restore and build

string is an alias in C# for System.String.
So technically, there is no difference. It's like int vs. System.Int32.

As far as guidelines, it's generally recommended to use string any time you're referring to an object.

e.g.

string place = "world";

Likewise, I think it's generally recommended to use String if you need to refer specifically to the class.

e.g.

string greet = String.Format("Hello {0}!", place);

This is the style that Microsoft tends to use in their examples.

It appears that the guidance in this area may have changed, as StyleCop now enforces the use of the C# specific aliases.

• Build solution will perform an incremental build: if it doesn't think it needs to rebuild a project, it won't. It may also use partially-built bits of the project if they haven't changed (I don't know how far it takes this)
• Rebuild solution will clean and then build the solution from scratch, ignoring anything it's done before. The difference between this and "Clean, followed by Build" is that Rebuild will clean-then-build each project, one at a time, rather than cleaning all and then building all.
• Clean solution will remove the build artifacts from the previous build. If there are any other files in the build target directories (bin and obj) they may not be removed, but actual build artifacts are. I've seen behaviour for this vary - sometimes deleting fairly thoroughly and sometimes not - but I'll give VS the benefit of the doubt for the moment :)

(The links are to the devenv.exe command line switches, but they do the same as the menu items.)