c# - Roslyn 向现有类添加新方法

Question

我正在研究在使用 VisualStudioWorkspace 更新现有代码的 Visual Studio 扩展 (VSIX) 中使用 Roslyn 编译器。在过去的几天里阅读了这篇文章，似乎有几种方法可以实现这一点......我只是不确定哪种方法对我来说最好。

好吧，让我们假设用户在 Visual Studio 2015 中打开了他们的解决方案。他们单击我的扩展并(通过表单)告诉我他们想要将以下方法定义添加到接口(interface):

GetSomeDataResponse GetSomeData(GetSomeDataRequest request);

他们还告诉我接口(interface)的名称，它是ITheInterface。

界面中已经有一些代码:

namespace TheProjectName.Interfaces
{
    using System;
    public interface ITheInterface
    {
        /// <summary>
        ///    A lonely method.
        /// </summary>
        LonelyMethodResponse LonelyMethod(LonelyMethodRequest request);
    }
}

好的，所以我可以使用以下方法加载接口(interface)文档:

Document myInterface = this.Workspace.CurrentSolution?.Projects?
    .FirstOrDefault(p 
        => p.Name.Equals("TheProjectName"))
    ?.Documents?
        .FirstOrDefault(d 
            => d.Name.Equals("ITheInterface.cs"));

那么，现在将我的新方法添加到这个现有接口(interface)的最佳方法是什么，最好也写在 XML 注释(三斜杠注释)中？请记住，请求和响应类型(GetSomeDataRequest 和 GetSomeDataResponse)可能实际上还不存在。我对此很陌生，所以如果您能提供代码示例，那就太好了。

更新

我决定(可能)最好的方法是简单地注入(inject)一些文本，而不是尝试以编程方式构建方法声明。

我尝试了以下方法，但最终出现了一个我不理解的异常:

SourceText sourceText = await myInterface.GetTextAsync();
string text = sourceText.ToString();
var sb = new StringBuilder();

// I want to all the text up to and including the last
// method, but without the closing "}" for the interface and the namespace
sb.Append(text.Substring(0, text.LastIndexOf("}", text.LastIndexOf("}") - 1)));

// Now add my method and close the interface and namespace.
sb.AppendLine("GetSomeDataResponse GetSomeData(GetSomeDataRequest request);");
sb.AppendLine("}");
sb.AppendLine("}");

检查一下，一切正常(我的真实代码添加了格式和 XML 注释，但为了清楚起见将其删除)。

所以，知道这些是不可变的，我尝试按如下方式保存它:

var updatedSourceText = SourceText.From(sb.ToString());
var newInterfaceDocument = myInterface.WithText(updatedSourceText);
var newProject = newInterfaceDocument.Project;
var newSolution = newProject.Solution;
this.Workspace.TryApplyChanges(newSolution);

但这会产生以下异常:

bufferAdapter is not a VsTextDocData 

at Microsoft.VisualStudio.Editor.Implementation.VsEditorAdaptersFactoryService.GetAdapter(IVsTextBuffer bufferAdapter) at Microsoft.VisualStudio.Editor.Implementation.VsEditorAdaptersFactoryService.GetDocumentBuffer(IVsTextBuffer bufferAdapter) at Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem.InvisibleEditor..ctor(IServiceProvider serviceProvider, String filePath, Boolean needsSave, Boolean needsUndoDisabled) at Microsoft.VisualStudio.LanguageServices.RoslynVisualStudioWorkspace.OpenInvisibleEditor(IVisualStudioHostDocument hostDocument) at Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem.DocumentProvider.StandardTextDocument.UpdateText(SourceText newText) at Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem.VisualStudioWorkspaceImpl.ApplyDocumentTextChanged(DocumentId documentId, SourceText newText) at Microsoft.CodeAnalysis.Workspace.ApplyProjectChanges(ProjectChanges projectChanges) at Microsoft.CodeAnalysis.Workspace.TryApplyChanges(Solution newSolution) at Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem.VisualStudioWorkspaceImpl.TryApplyChanges(Solution newSolution)

Answer 1

如果我是你，我会利用 Roslyn 的所有优势，即我会使用 Document 的 SyntaxTree 而不是处理文件文本(你可以在根本不使用 Roslyn 的情况下执行后者)。

例如:

...
SyntaxNode root = await document.GetSyntaxRootAsync().ConfigureAwait(false);
var interfaceDeclaration = root.DescendantNodes(node => node.IsKind(SyntaxKind.InterfaceDeclaration)).FirstOrDefault() as InterfaceDeclarationSyntax;
if (interfaceDeclaration == null) return;

var methodToInsert= GetMethodDeclarationSyntax(returnTypeName: "GetSomeDataResponse ", 
          methodName: "GetSomeData", 
          parameterTypes: new[] { "GetSomeDataRequest" }, 
          paramterNames: new[] { "request" });
var newInterfaceDeclaration = interfaceDeclaration.AddMembers(methodToInsert);

var newRoot = root.ReplaceNode(interfaceDeclaration, newInterfaceDeclaration);

// this will format all nodes that have Formatter.Annotation
newRoot = Formatter.Format(newRoot, Formatter.Annotation, workspace);
workspace.TryApplyChanges(document.WithSyntaxRoot(newRoot).Project.Solution);
...

public MethodDeclarationSyntax GetMethodDeclarationSyntax(string returnTypeName, string methodName, string[] parameterTypes, string[] paramterNames)
{
    var parameterList = SyntaxFactory.ParameterList(SyntaxFactory.SeparatedList(GetParametersList(parameterTypes, paramterNames)));
    return SyntaxFactory.MethodDeclaration(attributeLists: SyntaxFactory.List<AttributeListSyntax>(), 
                  modifiers: SyntaxFactory.TokenList(), 
                  returnType: SyntaxFactory.ParseTypeName(returnTypeName), 
                  explicitInterfaceSpecifier: null, 
                  identifier: SyntaxFactory.Identifier(methodName), 
                  typeParameterList: null, 
                  parameterList: parameterList, 
                  constraintClauses: SyntaxFactory.List<TypeParameterConstraintClauseSyntax>(), 
                  body: null, 
                  semicolonToken: SyntaxFactory.Token(SyntaxKind.SemicolonToken))
          // Annotate that this node should be formatted
          .WithAdditionalAnnotations(Formatter.Annotation);
}

private IEnumerable<ParameterSyntax> GetParametersList(string[] parameterTypes, string[] paramterNames)
{
    for (int i = 0; i < parameterTypes.Length; i++)
    {
        yield return SyntaxFactory.Parameter(attributeLists: SyntaxFactory.List<AttributeListSyntax>(),
                                                 modifiers: SyntaxFactory.TokenList(),
                                                 type: SyntaxFactory.ParseTypeName(parameterTypes[i]),
                                                 identifier: SyntaxFactory.Identifier(paramterNames[i]),
                                                 @default: null);
    }
}

请注意，这是非常原始的代码，Roslyn API 在分析/处理语法树、获取符号信息/引用等方面非常强大。我建议你看看这个 page还有这个page供引用。