public override async Task ComputeRefactoringsAsync(CodeRefactoringContext context)
{
var document = context.Document;
if (document.Project.Solution.Workspace.Kind == WorkspaceKind.MiscellaneousFiles)
{
return;
}
var span = context.Span;
if (!span.IsEmpty)
{
return;
}
var cancellationToken = context.CancellationToken;
if (cancellationToken.IsCancellationRequested)
{
return;
}
var root = await document.GetSyntaxRootAsync(cancellationToken);
var model = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
if (model.IsFromGeneratedCode(cancellationToken))
{
return;
}
var node = root.FindNode(span) as BinaryExpressionSyntax;
if (node == null || !node.OperatorToken.IsKind(SyntaxKind.QuestionQuestionToken))
{
return;
}
context.RegisterRefactoring(
CodeActionFactory.Create(
span,
DiagnosticSeverity.Info,
GettextCatalog.GetString("Replace '??' operator with '?:' expression"), t2 =>
{
var left = node.Left;
var info = model.GetTypeInfo(left, t2);
if (info.ConvertedType.IsNullableType())
{
left = SyntaxFactory.MemberAccessExpression(SyntaxKind.SimpleMemberAccessExpression, FlipEqualsTargetAndArgumentCodeRefactoringProvider.AddParensIfRequired(left), SyntaxFactory.IdentifierName("Value"));
}
var ternary = SyntaxFactory.ConditionalExpression(
SyntaxFactory.BinaryExpression(
SyntaxKind.NotEqualsExpression,
node.Left,
SyntaxFactory.LiteralExpression(SyntaxKind.NullLiteralExpression)
),
left,
node.Right
).WithAdditionalAnnotations(Formatter.Annotation);
return(Task.FromResult(document.WithSyntaxRoot(root.ReplaceNode((SyntaxNode)node, (ExpressionSyntax)ternary))));
}
)
);
}
static Document PerformAction(Document document, SyntaxNode root, BinaryExpressionSyntax bop)
{
var nodeToReplace = bop.IsParentKind(SyntaxKind.ParenthesizedExpression) ? bop.Parent : bop;
var castExpr = (ExpressionSyntax)SyntaxFactory.CastExpression(bop.Right as TypeSyntax, FlipEqualsTargetAndArgumentCodeRefactoringProvider.AddParensIfRequired(bop.Left.WithoutLeadingTrivia().WithoutTrailingTrivia())).WithLeadingTrivia(bop.GetLeadingTrivia()).WithTrailingTrivia(bop.GetTrailingTrivia());
var newRoot = root.ReplaceNode((SyntaxNode)nodeToReplace, castExpr);
return(document.WithSyntaxRoot(newRoot));
}