以编程方式将 using 指令添加到 class

Question

我正在研究Visual Studio可扩展性。 MSDN 中的这段代码创建了一个新的 C# 解决方案，其中包含一个带有 class 的项目：

EnvDTE.DTE dte =   this.GetService(typeof(Microsoft.VisualStudio.Shell.Interop.SDTE)) as EnvDTE.DTE;
EnvDTE80.Solution2 solution = (EnvDTE80.Solution2)dte.Solution;
try {
    solution.Create(@"F:\Dev\Visual Studio 2013\Packages\Spikes\VSPNewSolution\Test\MySolution", "MySolution");

    string templatePath = solution.GetProjectTemplate("ConsoleApplication.zip", "CSharp");
    string projectPath = @"F:\Dev\Visual Studio 2013\Packages\Spikes\VSPNewSolution\Test\MySolution\MyProject";

    /*
     * from MZTools site :
     * Once you have the template file name, you can add a project to the solution using the EnvDTE80.Solution.AddFromTemplate method.
     * Note: this method returns null (Nothing) rather than the EnvDTE.Project created, 
     * so you may need to locate the created project in the Solution.Projects collection. 
     * See PRB: Solution.AddXXX and ProjectItems.AddXXX methods return Nothing (null).
     */
    EnvDTE.Project project = solution.AddFromTemplate(templatePath, projectPath, "MyProject", false);

    EnvDTE.ProjectItem projectItem;
    String itemPath;

    // Point to the first project
    project = solution.Projects.Item(1); // try also "MyProject"

    VSLangProj.VSProject vsProject = (VSLangProj.VSProject)project.Object;
    vsProject.References.Add("NUnit.Framework");

    // Retrieve the path to the class template.
    itemPath = solution.GetProjectItemTemplate("Class.zip", "CSharp");

    //Create a new project item based on the template, in this case, a Class.
    projectItem = project.ProjectItems.AddFromTemplate(itemPath, "MyClass.cs");
}
catch (Exception ex) {
    System.Windows.Forms.MessageBox.Show("ERROR: " + ex.Message);
}

我设法使用 VSLangProj 添加对 MyProject 的引用。
到目前为止，还不错。
结果 class 是：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace MyProject
{
    class MyClass
    {
    }
}

经过大量谷歌搜索后我没有找到的是添加 using 指令的方法在 class 代码中（ 在这种情况下使用 NUnit.Framework；）。
简单的方法是编写直接操作 class 文档的行。
有没有办法使用 Visual Studio Extensibility 以编程方式执行此操作？

更新

在尝试为创建的 class 获取 CodeClass 对象之后，我尝试了 Finding a ProjectItem by type name via DTE 中发布的代码变化不大。这是更新后的代码：

EnvDTE.DTE dte = this.GetService(typeof(Microsoft.VisualStudio.Shell.Interop.SDTE)) as EnvDTE.DTE;
EnvDTE80.Solution2 solution = (EnvDTE80.Solution2)dte.Solution;
try {

    string solutionPath = @"F:\Dev\Visual Studio 2013\Packages\Spikes\VSPNewSolution\Test\MySolution";
    solution.Create(solutionPath, "MySolution");

    string templatePath = solution.GetProjectTemplate("ConsoleApplication.zip", "CSharp");
    string projectPath = @"F:\Dev\Visual Studio 2013\Packages\Spikes\VSPNewSolution\Test\MySolution\MyProject";

    EnvDTE.Project project = solution.AddFromTemplate(templatePath, projectPath, "MyProject", false);

    EnvDTE.ProjectItem projectItem;
    String itemPath;

    foreach (EnvDTE.Project p in solution.Projects) {
        if (p.Name == "MyProject") {
            project = p;
            break;
        }
    }

    VSLangProj.VSProject vsProject = (VSLangProj.VSProject)project.Object;
    vsProject.References.Add("NUnit.Framework");

    itemPath = solution.GetProjectItemTemplate("Class.zip", "CSharp");
    projectItem = project.ProjectItems.AddFromTemplate(itemPath, "MyClass.cs");

    // I decided to save both, just in case
    solution.SaveAs(solutionPath + @"\MySolution.sln");
    project.Save();

    EnvDTE.CodeClass codeClass = FindClass(project, "MyClass.cs");

    // Display the source code for the class (from MSDN).

    if (codeClass != null) {
        EnvDTE.TextPoint start = codeClass.GetStartPoint(EnvDTE.vsCMPart.vsCMPartWhole);
        EnvDTE.TextPoint finish = codeClass.GetEndPoint(EnvDTE.vsCMPart.vsCMPartWhole);
        string src = start.CreateEditPoint().GetText(finish);
        System.Windows.Forms.MessageBox.Show(src, codeClass.FullName + "Source"); 
    }
}
catch (Exception ex) {
    System.Windows.Forms.MessageBox.Show("ERROR: " + ex.Message);
    }
}

private CodeClass FindClass(Project project, string className) {
    return FindClass(project.CodeModel.CodeElements, className);
}

private CodeClass FindClass(CodeElements elements, string className) {
    foreach (CodeElement element in elements) {
        if (element is CodeNamespace || element is CodeClass) {
            CodeClass c = element as CodeClass;
            if (c != null && c.Access == vsCMAccess.vsCMAccessPublic) {
                if (c.FullName == className)
                    return c;

                CodeClass subClass = FindClass(c.Members, className);
                if (subClass != null)
                    return subClass;
            }

            CodeNamespace ns = element as CodeNamespace;
            if (ns != null) {
                CodeClass cc = FindClass(ns.Members, className);
                if (cc != null)
                    return cc;
            }
        }
    }
    return null;
}

嗯，事实证明 FindClass 总是 return 为空，因为 project.CodeModel.CodeElements.Count 为零。呃？

更新 2
好吧，请不要打败 me.The 原始代码在 projectPath 变量中有多余的反斜杠。
这导致 project.CodeModel.CodeElements.Count 为零。
此外，FindClass 需要没有扩展名的 class FullName 并搜索 public class仅供参考。
我更正了代码，但在 return 中仍然得到 null（我想是我自己的错：我一定是漏掉了什么）。
无论如何，FindClass 在 all 项目 CodeElements 中搜索给定的 class，包括 classes 项目引用。
这对我来说有点过分了，因为我正在搜索项目本地的 class。
所以我写了一个函数来做到这一点。
在这里：

public static CodeClass FindClassInProjectItems(Project project, string className) {
            CodeClass result = null;
            foreach (EnvDTE.ProjectItem pi in project.ProjectItems) {                
                if (pi.Name == className + ".cs") {
                    if (pi.FileCodeModel != null) {
                        foreach (EnvDTE.CodeElement ce in pi.FileCodeModel.CodeElements) {
                            if (ce is EnvDTE.CodeClass) {
                                result = ce as EnvDTE.CodeClass;
                                break;
                            }
                            else if (ce is EnvDTE.CodeNamespace) {
                                CodeNamespace ns = ce as CodeNamespace;

                                if (ns.Name == project.Name) {
                                    foreach (CodeElement sce in ns.Members) {
                                        if (sce is CodeClass && sce.Name == className) {
                                            result = sce as CodeClass;
                                            break;
                                        }
                                    }
                                }                                    
                            }
                        }
                    }
                }        
            }
            return result;
        }

它有效，所以我创建了一个静态 ClassFinder class 并添加了该函数。
下一步是检索完整的 class 源代码，包括 using 指令。
我在 MSDN here 上找到了一个示例，这是关键代码：

// Display the source code for the class.
TextPoint start = cls.GetStartPoint(vsCMPart.vsCMPartWhole);
TextPoint finish = cls.GetEndPoint(vsCMPart.vsCMPartWhole);
string src = start.CreateEditPoint().GetText(finish);

实际上，第一行抛出异常。
所以我尝试了 vsCMPart 枚举的所有成员：他们中的大多数抛出异常，除了： vsCMPart.vsCMPartBody, vsCMPart.vsCMPartHeader, vsCMPart.vsCMPartNavigate and vsCMPart.vsCMPartWholeWithAttributes.
vsCMPart.vsCMPartHeader和vsCMPart.vsCMPartWholeWithAttributesreturn相同的结果（至少在这种情况下），
而其他人则没有 return 整个代码。
保持简短：

private void DisplayClassSource(CodeClass codeClass) {
    EnvDTE.TextPoint start = codeClass.GetStartPoint(vsCMPart.vsCMPartHeader);
    EnvDTE.TextPoint finish = codeClass.GetEndPoint();
    string source = start.CreateEditPoint().GetText(finish);        
    System.Windows.Forms.MessageBox.Show(source, codeClass.FullName + "Class source");
}   

private void DisplayNamespaceSource(CodeNamespace codeNamespace) {
    EnvDTE.TextPoint start = codeNamespace.GetStartPoint(EnvDTE.vsCMPart.vsCMPartWholeWithAttributes);
    EnvDTE.TextPoint finish = codeNamespace.GetEndPoint();
    string src = start.CreateEditPoint().GetText(finish);
    System.Windows.Forms.MessageBox.Show(src, codeNamespace.FullName + "Namespace source");
}

如果我们想要 IDE 中显示的源代码，包括 using 指令，
我们必须使用 classCode.ProjectItem 对象：

    private void DisplayClassFullSource(CodeClass codeClass) {
        System.Text.StringBuilder sb = new System.Text.StringBuilder();
        foreach (CodeElement ce in codeClass.ProjectItem.FileCodeModel.CodeElements) {
            if (ce.Kind == vsCMElement.vsCMElementImportStmt) {
                // this is a using directive
                // ce.Name throws an exception here !
                sb.AppendLine(GetImportCodeLines(ce));
            }
            else if (ce.Kind == vsCMElement.vsCMElementNamespace) {
                sb.AppendLine();
                sb.AppendLine(GetNamespaceCodeLines(ce));
            }
        }

        System.Windows.Forms.MessageBox.Show(sb.ToString(), codeClass.FullName + "class source");
    }

    private static string GetImportCodeLines(CodeElement ce) {
        TextPoint start = ce.GetStartPoint(vsCMPart.vsCMPartWholeWithAttributes);
        TextPoint finish = ce.GetEndPoint(vsCMPart.vsCMPartWholeWithAttributes);
        return start.CreateEditPoint().GetText(finish);
    }

    private string GetNamespaceCodeLines(CodeElement ce) {
        EnvDTE.TextPoint start = ce.GetStartPoint(vsCMPart.vsCMPartWholeWithAttributes);
        //EnvDTE.TextPoint finish = codeClass.GetEndPoint(EnvDTE.vsCMPart.vsCMPartWhole); // ERROR : the method or operation is not implemented
        EnvDTE.TextPoint finish = ce.GetEndPoint();
        return start.CreateEditPoint().GetText(finish);
    }

现在我们已经非常接近问题的解决方案了。看我的回答。（对不起，如果这看起来像小说）

Answer 1

据我所知，没有直接的方法可以将 using 指令添加到 CodeClass。
我找到的唯一方法是：
它当然需要改进，但它确实有效。
此代码假定所有 using 指令都排成一行，位于 class 代码的顶部。
例如，如果命名空间中存在 using 指令，它将无法正常工作。
它会在最后找到的指令之后添加给定的指令。
它 而不是 检查代码以确定指令是否已经存在。

    private void AddUsingDirectiveToClass(CodeClass codeClass, string directive) {
        CodeElement lastUsingDirective = null;

        foreach (CodeElement ce in codeClass.ProjectItem.FileCodeModel.CodeElements) {
            if (ce.Kind == vsCMElement.vsCMElementImportStmt) {
                // save it
                lastUsingDirective = ce;
            }
            else {
                if (lastUsingDirective != null) {
                    // insert given directive after the last one, on a new line
                    EditPoint insertPoint = lastUsingDirective.GetEndPoint().CreateEditPoint();
                    insertPoint.Insert("\r\nusing " + directive + ";");
                }
            }
        }
    }

所以，最终的工作代码是

        EnvDTE.DTE dte = this.GetService(typeof(Microsoft.VisualStudio.Shell.Interop.SDTE)) as EnvDTE.DTE;
        EnvDTE80.Solution2 solution = (EnvDTE80.Solution2)dte.Solution;
        try {
            /*
             * NOTE while the MSDN sample states you must open an existing solution for the code to work,
             * it works also without opening a solution.
             */
            string solutionPath = @"F:\Dev\Visual Studio 2013\Packages\Spikes\VSPNewSolution\Test\MySolution";
            solution.Create(solutionPath, "MySolution");

            string templatePath = solution.GetProjectTemplate("ConsoleApplication.zip", "CSharp");
            string projectPath = solutionPath + @"\MyProject";

            /*
             * from MZTools site :
             * Once you have the template file name, you can add a project to the solution using the EnvDTE80.Solution.AddFromTemplate method.
             * Note: this method returns null (Nothing) rather than the EnvDTE.Project created, 
             * so you may need to locate the created project in the Solution.Projects collection. 
             * See PRB: Solution.AddXXX and ProjectItems.AddXXX methods return Nothing (null).
             */
            EnvDTE.Project project = solution.AddFromTemplate(templatePath, projectPath, "MyProject", false); 

            // the following code would do since there is only a single project
            //project = solution.Projects.Item(1); 

            // tried this :
            // project = solution.Projects.Item("MyProject"); 
            // but it throws an invalid argument exception

            // search project by name
            foreach (EnvDTE.Project p in solution.Projects) {
                if (p.Name == "MyProject") {
                    project = p;
                    break;
                }
            }

            // add a reference to NUnit
            VSLangProj.VSProject vsProject = (VSLangProj.VSProject)project.Object;
            vsProject.References.Add("NUnit.Framework");

            // Retrieve the path to the class template.
            string itemPath = solution.GetProjectItemTemplate("Class.zip", "CSharp");

            //Create a new project item based on the template, in this case, a Class.

            /*
             * Here we find the same problem as with solution.AddFromTemplate(...) ( see above )
             */
            EnvDTE.ProjectItem projectItem = project.ProjectItems.AddFromTemplate(itemPath, "MyClass.cs");

            solution.SaveAs(solutionPath + @"\MySolution.sln");                                
            project.Save();

            // retrieve the new class we just created
            EnvDTE.CodeClass codeClass = ClassFinder.FindClassInProjectItems(project, "MyClass");                               

            if (codeClass != null) {
                DisplayClassFullSource(codeClass);
                AddUsingDirectiveToClass(codeClass, "NUnit.Framework");
                project.Save();
                DisplayClassFullSource(codeClass);
            }


        }
        catch (Exception ex) {
            System.Windows.Forms.MessageBox.Show("ERROR: " + ex.Message);
        }            
    }

P.S.
在接受这个答案之前，我会等一会儿，以防其他人发布更好的解决方案。

编辑
时间过去了，没有关于该主题的进一步帖子。我将此标记为已接受的答案。

以编程方式将 using 指令添加到 class

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