你如何循环当前加载的程序集？

Question

我的 ASP.NET 应用程序中有一个“诊断”页面，它执行验证数据库连接、显示当前 appSettings 和 ConnectionStrings 等操作。此页面的一部分显示重要的程序集版本始终使用的类型，但我不知道如何有效地显示所有已加载程序集的版本。

找出 .NET 应用程序中所有当前引用和/或加载的程序集的最有效方法是什么？

注意：我对基于文件的方法不感兴趣，比如在特定目录中迭代 *.dll。我对应用程序现在实际使用的内容感兴趣。

Answer 1

获取当前AppDomain的加载程序集：

var loadedAssemblies = AppDomain.CurrentDomain.GetAssemblies();

获取另一个程序集引用的程序集：

var referencedAssemblies = someAssembly.GetReferencedAssemblies();

请注意，如果程序集 A 引用程序集 B 并且程序集 A 已加载，这并不意味着程序集 B 也已加载。仅在需要时才加载程序集 B。因此，GetReferencedAssemblies() 返回 AssemblyName 实例而不是 Assembly 实例。

Answer 2

此扩展方法以递归方式获取所有引用的程序集，包括嵌套程序集。

由于它使用ReflectionOnlyLoad，它会将程序集加载到单独的 AppDomain 中，这具有不干扰 JIT 进程的优点。

您会注意到还有一个MyGetMissingAssembliesRecursive。您可以使用它来检测任何缺少的程序集，这些程序集被引用但由于某种原因不在当前目录中。这在使用MEF 时非常有用。返回列表将为您提供丢失的程序集以及拥有它的人（其父级）。

/// <summary>
///     Intent: Get referenced assemblies, either recursively or flat. Not thread safe, if running in a multi
///     threaded environment must use locks.
/// </summary>
public static class GetReferencedAssemblies
{
    static void Demo()
    {
        var referencedAssemblies = Assembly.GetEntryAssembly().MyGetReferencedAssembliesRecursive();
        var missingAssemblies = Assembly.GetEntryAssembly().MyGetMissingAssembliesRecursive();
        // Can use this within a class.
        //var referencedAssemblies = this.MyGetReferencedAssembliesRecursive();
    }

    public class MissingAssembly
    {
        public MissingAssembly(string missingAssemblyName, string missingAssemblyNameParent)
        {
            MissingAssemblyName = missingAssemblyName;
            MissingAssemblyNameParent = missingAssemblyNameParent;
        }

        public string MissingAssemblyName { get; set; }
        public string MissingAssemblyNameParent { get; set; }
    }

    private static Dictionary<string, Assembly> _dependentAssemblyList;
    private static List<MissingAssembly> _missingAssemblyList;

    /// <summary>
    ///     Intent: Get assemblies referenced by entry assembly. Not recursive.
    /// </summary>
    public static List<string> MyGetReferencedAssembliesFlat(this Type type)
    {
        var results = type.Assembly.GetReferencedAssemblies();
        return results.Select(o => o.FullName).OrderBy(o => o).ToList();
    }

    /// <summary>
    ///     Intent: Get assemblies currently dependent on entry assembly. Recursive.
    /// </summary>
    public static Dictionary<string, Assembly> MyGetReferencedAssembliesRecursive(this Assembly assembly)
    {
        _dependentAssemblyList = new Dictionary<string, Assembly>();
        _missingAssemblyList = new List<MissingAssembly>();

        InternalGetDependentAssembliesRecursive(assembly);

        // Only include assemblies that we wrote ourselves (ignore ones from GAC).
        var keysToRemove = _dependentAssemblyList.Values.Where(
            o => o.GlobalAssemblyCache == true).ToList();

        foreach (var k in keysToRemove)
        {
            _dependentAssemblyList.Remove(k.FullName.MyToName());
        }

        return _dependentAssemblyList;
    }

    /// <summary>
    ///     Intent: Get missing assemblies.
    /// </summary>
    public static List<MissingAssembly> MyGetMissingAssembliesRecursive(this Assembly assembly)
    {
        _dependentAssemblyList = new Dictionary<string, Assembly>();
        _missingAssemblyList = new List<MissingAssembly>();
        InternalGetDependentAssembliesRecursive(assembly);

        return _missingAssemblyList;
    }

    /// <summary>
    ///     Intent: Internal recursive class to get all dependent assemblies, and all dependent assemblies of
    ///     dependent assemblies, etc.
    /// </summary>
    private static void InternalGetDependentAssembliesRecursive(Assembly assembly)
    {
        // Load assemblies with newest versions first. Omitting the ordering results in false positives on
        // _missingAssemblyList.
        var referencedAssemblies = assembly.GetReferencedAssemblies()
            .OrderByDescending(o => o.Version);

        foreach (var r in referencedAssemblies)
        {
            if (String.IsNullOrEmpty(assembly.FullName))
            {
                continue;
            }

            if (_dependentAssemblyList.ContainsKey(r.FullName.MyToName()) == false)
            {
                try
                {
                    var a = Assembly.ReflectionOnlyLoad(r.FullName);
                    _dependentAssemblyList[a.FullName.MyToName()] = a;
                    InternalGetDependentAssembliesRecursive(a);
                }
                catch (Exception ex)
                {
                    _missingAssemblyList.Add(new MissingAssembly(r.FullName.Split(',')[0], assembly.FullName.MyToName()));
                }
            }
        }
    }

    private static string MyToName(this string fullName)
    {
        return fullName.Split(',')[0];
    }
}

更新

为了使这个代码线程安全，在它周围加上一个lock。默认情况下它目前不是线程安全的，因为它引用了一个共享的静态全局变量来发挥它的魔力。