C# RefactoringContext类代码示例

		public IEnumerable<CodeAction> GetActions(RefactoringContext context)
		{
			var expr = GetCreatePropertyOrFieldNode(context);
			if (expr == null)
				yield break;
			if (!(expr is MemberReferenceExpression))
				yield break;
			var propertyName = CreatePropertyAction.GetPropertyName(expr);
			if (propertyName == null)
				yield break;
			if (IsInvocationTarget(expr))
				yield break;
			var statement = expr.GetParent<Statement>();
			if (statement == null)
				yield break;
			if (!(context.Resolve(expr).IsError))
				yield break;
			var guessedType = CreateFieldAction.GuessType(context, expr);
			if (guessedType == null || guessedType.Kind != TypeKind.Enum)
				yield break;
			var state = context.GetResolverStateBefore(expr);
			if (state.CurrentMember == null || state.CurrentTypeDefinition == null)
				yield break;

			yield return new CodeAction(context.TranslateString("Create enum value"), script => {
				var decl = new EnumMemberDeclaration {
					Name = propertyName
				};
				script.InsertWithCursor(context.TranslateString("Create enum value"), guessedType.GetDefinition (), decl);
			});
			
		}

		public IEnumerable<CodeAction> GetActions(RefactoringContext context)
		{
			var type = context.GetNode<AstType>();
			if (type == null || type.Role != Roles.BaseType)
				yield break;
			var state = context.GetResolverStateBefore(type);
			if (state.CurrentTypeDefinition == null)
				yield break;

			var resolveResult = context.Resolve(type);
			if (resolveResult.Type.Kind != TypeKind.Interface)
				yield break;

			var toImplement = ImplementInterfaceAction.CollectMembersToImplement(
				state.CurrentTypeDefinition,
				resolveResult.Type,
				false
			);
			if (toImplement.Count == 0)
				yield break;

			yield return new CodeAction(context.TranslateString("Implement interface explicit"), script => {
				script.InsertWithCursor(
					context.TranslateString("Implement Interface"),
					state.CurrentTypeDefinition,
					ImplementInterfaceAction.GenerateImplementation (context, toImplement.Select (t => Tuple.Create (t.Item1, true)))
				);
			});
		}

		static SwitchStatement GetSwitchStatement (RefactoringContext context)
		{
			var switchStatment = context.GetNode<SwitchStatement> ();
			if (switchStatment != null && switchStatment.SwitchSections.Count == 0)
				return switchStatment;
			return null;
		}

		CodeAction CreateFromExpression(RefactoringContext context, Expression expression)
		{
			var resolveResult = context.Resolve(expression);
			if (resolveResult.IsError)
				return null;
			
			return new CodeAction(context.TranslateString("Extract method"), script => {
				string methodName = "NewMethod";
				var method = new MethodDeclaration() {
					ReturnType = context.CreateShortType(resolveResult.Type),
					Name = methodName,
					Body = new BlockStatement() {
						new ReturnStatement(expression.Clone())
					}
				};
				if (!StaticVisitor.UsesNotStaticMember(context, expression))
					method.Modifiers |= Modifiers.Static;
				var task = script.InsertWithCursor(context.TranslateString("Extract method"), Script.InsertPosition.Before, method);

				Action<Task> replaceStatements = delegate {
					var target = new IdentifierExpression(methodName);
					script.Replace(expression, new InvocationExpression(target));
					script.Link(target, method.NameToken);
				};

				if (task.IsCompleted) {
					replaceStatements (null);
				} else {
					task.ContinueWith (replaceStatements, TaskScheduler.FromCurrentSynchronizationContext ());
				}
			});
		}

		static VariableDeclarationStatement GetVariableDeclarationStatement (RefactoringContext context)
		{
			var result = context.GetNode<VariableDeclarationStatement> ();
			if (result != null && result.Variables.Count == 1 && !result.Variables.First ().Initializer.IsNull && result.Type.Contains (context.Location) && !result.Type.IsVar ())
				return result;
			return null;
		}

        IEnumerable<CodeAction> GetActionsForAddNamespaceUsing(RefactoringContext context, AstNode node)
        {
            var nrr = context.Resolve(node) as NamespaceResolveResult;
            if (nrr == null)
                return EmptyList<CodeAction>.Instance;

            var trr = context.Resolve(node.Parent) as TypeResolveResult;
            if (trr == null)
                return EmptyList<CodeAction>.Instance;
            ITypeDefinition typeDef = trr.Type.GetDefinition();
            if (typeDef == null)
                return EmptyList<CodeAction>.Instance;

            IList<IType> typeArguments;
            ParameterizedType parameterizedType = trr.Type as ParameterizedType;
            if (parameterizedType != null)
                typeArguments = parameterizedType.TypeArguments;
            else
                typeArguments = EmptyList<IType>.Instance;

            var resolver = context.GetResolverStateBefore(node.Parent);
            if (resolver.ResolveSimpleName(typeDef.Name, typeArguments) is UnknownIdentifierResolveResult) {
                // It's possible to remove the explicit namespace usage and introduce a using instead
                return new[] { NewUsingAction(context, node, typeDef.Namespace) };
            }
            return EmptyList<CodeAction>.Instance;
        }

        public IEnumerable<CodeAction> GetActions(RefactoringContext context)
        {
            if (context.IsSomethingSelected) {
                yield break;
            }
            AstType type;
            var varDecl = GetVariableDeclarationStatement(context, out type);
            if (varDecl == null) {
                yield break;
            }
            yield return new CodeAction(context.TranslateString("Split local variable declaration and assignment"), script => {
                var assign = new AssignmentExpression (new IdentifierExpression (varDecl.Variables.First().Name), AssignmentOperatorType.Assign, varDecl.Variables.First().Initializer.Clone());

                var newVarDecl = (VariableDeclarationStatement)varDecl.Clone();
                newVarDecl.Role = BlockStatement.StatementRole;

                if (newVarDecl.Type.IsMatch(new SimpleType ("var"))) {
                    newVarDecl.Type = type;
                }

                newVarDecl.Variables.First().Initializer = Expression.Null;

                script.InsertBefore(varDecl, newVarDecl);
                script.Replace(varDecl, varDecl.Parent is ForStatement ? (AstNode)assign : new ExpressionStatement (assign));
            }, varDecl.Variables.First ().AssignToken);
        }

		static AnonymousMethodExpression GetAnonymousMethodExpression (RefactoringContext context, out ITypeDefinition delegateType)
		{
			delegateType = null;
			
			var anonymousMethodExpression = context.GetNode<AnonymousMethodExpression> ();
			if (anonymousMethodExpression == null || !anonymousMethodExpression.DelegateToken.Contains (context.Location.Line, context.Location.Column) || anonymousMethodExpression.HasParameterList)
				return null;
			
			AstType resolvedType = null;
			var parent = anonymousMethodExpression.Parent;
			if (parent is AssignmentExpression) {
				resolvedType = context.ResolveType (((AssignmentExpression)parent).Left);
			} else if (parent is VariableDeclarationStatement) {
				resolvedType = context.ResolveType (((VariableDeclarationStatement)parent).Type);
			} else if (parent is InvocationExpression) {
				// TODO: handle invocations
			}
			
			if (resolvedType == null)
				return null;
			delegateType = context.GetDefinition (resolvedType);
			if (delegateType == null || delegateType.ClassType != ClassType.Delegate) 
				return null;
			
			return anonymousMethodExpression;
		}

		public override IEnumerable<CodeAction> GetActions(RefactoringContext context)
		{
			var service = (CodeGenerationService)context.GetService(typeof(CodeGenerationService)); 
			if (service == null)
				yield break;

			var type = context.GetNode<AstType>();
			if (type == null || type.Role != Roles.BaseType)
				yield break;
			var state = context.GetResolverStateBefore(type);
			if (state.CurrentTypeDefinition == null)
				yield break;

			var resolveResult = context.Resolve(type);
			if (resolveResult.Type.Kind != TypeKind.Interface)
				yield break;

			bool interfaceMissing;
			var toImplement = ImplementInterfaceAction.CollectMembersToImplement(
				state.CurrentTypeDefinition,
				resolveResult.Type,
				false,
				out interfaceMissing
			);
			if (toImplement.Count == 0)
				yield break;

			yield return new CodeAction(context.TranslateString("Implement interface explicit"), script =>
				script.InsertWithCursor(
					context.TranslateString("Implement Interface"),
					state.CurrentTypeDefinition,
					(s, c) => ImplementInterfaceAction.GenerateImplementation (c, toImplement.Select (t => Tuple.Create (t.Item1, true)), interfaceMissing).ToList()
				)
			, type);
		}

		public override IEnumerable<CodeAction> GetActions(RefactoringContext context)
		{
			var property = context.GetNode<PropertyDeclaration>();
			if (property == null || !property.NameToken.Contains(context.Location))
				yield break;

			var field = GetBackingField(context, property);
			if (!IsValidField(field, property.GetParent<TypeDeclaration>())) {
				yield break;
			}
			// create new auto property
			var newProperty = (PropertyDeclaration)property.Clone();
			newProperty.Getter.Body = BlockStatement.Null;
			newProperty.Setter.Body = BlockStatement.Null;
			
			yield return new CodeAction(context.TranslateString("Convert to auto property"), script => {
				script.Rename((IEntity)field, newProperty.Name);
				var oldField = context.RootNode.GetNodeAt<FieldDeclaration>(field.Region.Begin);
				if (oldField.Variables.Count == 1) {
					script.Remove(oldField);
				} else {
					var newField = (FieldDeclaration)oldField.Clone();
					foreach (var init in newField.Variables) {
						if (init.Name == field.Name) {
							init.Remove();
							break;
						}
					}
					script.Replace(oldField, newField);
				}
				script.Replace (property, newProperty);
			}, property.NameToken);
		}

		public override IEnumerable<CodeAction> GetActions(RefactoringContext context)
		{
			if (context.IsSomethingSelected) {
				yield break;
			}
			var node = context.GetNode<VariableDeclarationStatement>();
			if (node == null || node.Variables.Count != 1) {
				yield break;
			}
			var initializer = node.Variables.First();
			if (!initializer.NameToken.Contains(context.Location) || initializer.Initializer.IsNull) {
				yield break;
			}
			var resolveResult = context.Resolve(initializer) as LocalResolveResult;
			if (resolveResult == null || resolveResult.IsError) {
				yield break;
			}
			var unit = context.RootNode as SyntaxTree;
			if (unit == null) {
				yield break;
			}
			yield return new CodeAction(context.TranslateString("Inline local variable"), script => {
				refFinder.FindLocalReferences(resolveResult.Variable, context.UnresolvedFile, unit, context.Compilation, (n, r) => script.Replace(n, AddParensIfRequired (n, initializer.Initializer.Clone())), default(CancellationToken));
				script.Remove(node);
			}, initializer);
		}

        public IEnumerable<CodeAction> GetActions(RefactoringContext context)
        {
            var createExpression = context.GetNode<Expression>() as ObjectCreateExpression;
            if (createExpression == null)
                yield break;

            var resolveResult = context.Resolve(createExpression) as CSharpInvocationResolveResult;
            if (resolveResult == null || !resolveResult.IsError || resolveResult.Member.DeclaringTypeDefinition == null || resolveResult.Member.DeclaringTypeDefinition.IsSealed || resolveResult.Member.DeclaringTypeDefinition.Region.IsEmpty)
                yield break;

            yield return new CodeAction(context.TranslateString("Create constructor"), script => {
                var decl = new ConstructorDeclaration() {
                    Name = resolveResult.Member.DeclaringTypeDefinition.Name,
                    Modifiers = Modifiers.Public,
                    Body = new BlockStatement() {
                        new ThrowStatement(new ObjectCreateExpression(context.CreateShortType("System", "NotImplementedException")))
                    }
                };
                decl.Parameters.AddRange(CreateMethodDeclarationAction.GenerateParameters(context, createExpression.Arguments));

                script.InsertWithCursor(
                    context.TranslateString("Create constructor"),
                    resolveResult.Member.DeclaringTypeDefinition,
                    decl
                );
            }, createExpression);
        }

		public static IEnumerable<AstNode> GenerateImplementation(RefactoringContext context, IEnumerable<Tuple<IMember, bool>> toImplement)
		{
			var nodes = new Dictionary<IType, List<AstNode>>();
			
			foreach (var member in toImplement) {
				if (!nodes.ContainsKey(member.Item1.DeclaringType)) 
					nodes [member.Item1.DeclaringType] = new List<AstNode>();
				nodes [member.Item1.DeclaringType].Add(GenerateMemberImplementation(context, member.Item1, member.Item2));
			}
			
			foreach (var kv in nodes) {
				if (kv.Key.Kind == TypeKind.Interface) {
					yield return new PreProcessorDirective(
						PreProcessorDirectiveType.Region,
						string.Format("{0} implementation", kv.Key.Name));
				} else {
					yield return new PreProcessorDirective(
						PreProcessorDirectiveType.Region,
						string.Format("implemented abstract members of {0}", kv.Key.Name));
				}
				foreach (var member in kv.Value)
					yield return member;
				yield return new PreProcessorDirective(
					PreProcessorDirectiveType.Endregion
				);
			}
		}

		static AnonymousMethodExpression GetAnonymousMethodExpression (RefactoringContext context, out IType delegateType)
		{
			delegateType = null;
			
			var anonymousMethodExpression = context.GetNode<AnonymousMethodExpression> ();
			if (anonymousMethodExpression == null || !anonymousMethodExpression.DelegateToken.Contains (context.Location) || anonymousMethodExpression.HasParameterList)
				return null;
			
			IType resolvedType = null;
			var parent = anonymousMethodExpression.Parent;
			
			if (parent is AssignmentExpression) {
				resolvedType = context.Resolve (((AssignmentExpression)parent).Left).Type;
			} else if (parent is VariableInitializer) {
				resolvedType = context.Resolve (((VariableDeclarationStatement)parent.Parent).Type).Type;
			} else if (parent is InvocationExpression) {
				// TODO: handle invocations
			}
			if (resolvedType == null)
				return null;
			delegateType = resolvedType;
			if (delegateType.Kind != TypeKind.Delegate) 
				return null;
			
			return anonymousMethodExpression;
		}

		CodeAction ActionFromUsingStatement(RefactoringContext context)
		{
			var initializer = context.GetNode<VariableInitializer>();
			if (initializer == null)
				return null;
			var initializerRR = context.Resolve(initializer) as LocalResolveResult;
			if (initializerRR == null)
				return null;
			var elementType = GetElementType(initializerRR, context);
			if (elementType == null)
				return null;
			var usingStatement = initializer.Parent.Parent as UsingStatement;
			if (usingStatement == null)
				return null;
			return new CodeAction(context.TranslateString("Iterate via foreach"), script => {
				var iterator = MakeForeach(new IdentifierExpression(initializer.Name), elementType, context);
				if (usingStatement.EmbeddedStatement is EmptyStatement) {
					var blockStatement = new BlockStatement();
					blockStatement.Statements.Add(iterator);
					script.Replace(usingStatement.EmbeddedStatement, blockStatement);
					script.FormatText(blockStatement);
				} else if (usingStatement.EmbeddedStatement is BlockStatement) {
					var anchorNode = usingStatement.EmbeddedStatement.FirstChild;
					script.InsertAfter(anchorNode, iterator);
					script.FormatText(usingStatement.EmbeddedStatement);
				}
			});
		}