Sort and remove (unused) using statements Roslyn script/code?

Question

Sort and remove (unused) using statements Roslyn script/code? I\'m looking for some .NET/Roslyn (compiler as service) code that can run through a project and sort and remov

Answer 1

Roslyn CTP September 2012 provides a GetUnusedImportDirectives() method, which is of great use here.

By modifying the OrganizeSolution sample project Matt referenced you can achieve both sorting and removing of (unused) using directives. An (outdated) version of this project can be found here: http://go.microsoft.com/fwlink/?LinkId=263977. It is outdated because document.GetUpdatedDocument() does not exist anymore,

var document = newSolution.GetDocument(documentId);
var transformation = document.OrganizeImports();
var newDocument = transformation.GetUpdatedDocument();

can be simplified to

var document = newSolution.GetDocument(documentId);
var newDocument = document.OrganizeImports();

Adding newDocument = RemoveUnusedImportDirectives(newDocument); and providing the following method will do the trick.

private static IDocument RemoveUnusedImportDirectives(IDocument document)
{
    var root = document.GetSyntaxRoot();
    var semanticModel = document.GetSemanticModel();

    // An IDocument can refer to both a CSharp as well as a VisualBasic source file.
    // Therefore we need to distinguish those cases and provide appropriate casts.  
    // Since the question was tagged c# only the CSharp way is provided.
    switch (document.LanguageServices.Language)
    {
        case LanguageNames.CSharp:
            var oldUsings = ((CompilationUnitSyntax)root).Usings;
            var unusedUsings = ((SemanticModel)semanticModel).GetUnusedImportDirectives();
            var newUsings = Syntax.List(oldUsings.Where(item => !unusedUsings.Contains(item)));
            root = ((CompilationUnitSyntax)root).WithUsings(newUsings);
            document = document.UpdateSyntaxRoot(root);
            break;

        case LanguageNames.VisualBasic:
            // TODO
            break;
    }
    return document;
}