ICSharpCode.Dompiler+Mono.Cecil->；如何为单个方法生成代码

我可以使用Mono.Cecil和ICSharpCode.Dompiler来生成类型或程序集的代码。

但是，如果我尝试为单个方法生成代码，我会得到一个错误"Object reference not set to a instance of a Object"

你们能给我一些提示吗？感谢大家的帮助。

为程序集中的所有类型生成代码的代码：

DirectoryInfo di = new DirectoryInfo(appPath);
FileInfo[] allAssemblies = di.GetFiles("*.dll");
foreach (var assemblyFile in allAssemblies)
{
    string pathToAssembly = assemblyFile.FullName;
    System.Reflection.Assembly assembly = System.Reflection.Assembly.ReflectionOnlyLoadFrom(pathToAssembly);
    Mono.Cecil.AssemblyDefinition assemblyDefinition = Mono.Cecil.AssemblyDefinition.ReadAssembly(pathToAssembly,parameters);
    AstBuilder astBuilder = null;
    foreach (var typeInAssembly in assemblyDefinition.MainModule.Types)
    {
        if (typeInAssembly.IsPublic)
        {
             Console.WriteLine("T:{0}", typeInAssembly.Name);
            //just reset the builder to include only code for a single type
            astBuilder = new AstBuilder(new ICSharpCode.Decompiler.DecompilerContext(assemblyDefinition.MainModule));
            astBuilder.AddType(typeInAssembly);
            StringWriter output = new StringWriter();
            astBuilder.GenerateCode(new PlainTextOutput(output));
            string result = output.ToString();
            output.Dispose();
        }
    }
}

为程序集中的所有公共方法生成代码的代码：

DirectoryInfo di = new DirectoryInfo(appPath);
FileInfo[] allAssemblies = di.GetFiles("*.dll");
foreach (var assemblyFile in allAssemblies)
{
    string pathToAssembly = assemblyFile.FullName;
    System.Reflection.Assembly assembly = System.Reflection.Assembly.ReflectionOnlyLoadFrom(pathToAssembly);
    Mono.Cecil.AssemblyDefinition assemblyDefinition = Mono.Cecil.AssemblyDefinition.ReadAssembly(pathToAssembly,parameters);
    AstBuilder astBuilder = null;
    foreach (var typeInAssembly in assemblyDefinition.MainModule.Types)
    {
        if (typeInAssembly.IsPublic)
        {
            Console.WriteLine("T:{0}", typeInAssembly.Name);
            foreach (var method in typeInAssembly.Methods)
            {
                //just reset the builder to include only code for a single method
                astBuilder = new AstBuilder(new ICSharpCode.Decompiler.DecompilerContext(assemblyDefinition.MainModule));
                astBuilder.AddMethod(method);
                if (method.IsPublic && !method.IsGetter && !method.IsSetter && !method.IsConstructor)
                {
                    Console.WriteLine("M:{0}", method.Name);
                    StringWriter output = new StringWriter();
                    astBuilder.GenerateCode(new PlainTextOutput(output));
                    string result = output.ToString();
                    output.Dispose();
                }
            }
        }
    }
}

astBuilder = new AstBuilder(new ICSharpCode.Decompiler.DecompilerContext(assemblyDefinition.MainModule) { CurrentType = typeInAssembly } );

public string getSourceCode(MethodDefinition methodDefinition)
{
    try
    {
        var csharpLanguage = new CSharpLanguage();
        var textOutput = new PlainTextOutput();
        var decompilationOptions = new DecompilationOptions();
        decompilationOptions.FullDecompilation = true;
        csharpLanguage.DecompileMethod(methodDefinition, textOutput, decompilationOptions);
        return textOutput.ToString();              
    }
    catch (Exception exception)
    {
        PublicDI.log.error("in getSourceCode: {0}", new object[] { exception.Message });
        return ("Error in creating source code from IL: " + exception.Message);
    }
}