您将无法获得一个名称空间中的所有类型，因为一个名称空间可以桥接多个程序集，但是您可以获得一个程序集中的所有类并检查它们是否属于该名称空间。

assembly .GetTypes()在本地程序集上工作，或者您可以先加载一个程序集，然后在其上调用GetTypes()。

Namespaces are actually rather passive in the design of the runtime and serve primarily as organizational tools. The Full Name of a type in .NET consists of the Namespace and Class/Enum/Etc. combined. If you only wish to go through a specific assembly, you would simply loop through the types returned by assembly.GetExportedTypes() checking the value of type.Namespace. If you were trying to go through all assemblies loaded in the current AppDomain it would involve using AppDomain.CurrentDomain.GetAssemblies()

对于特定的程序集，命名空间和ClassName:

var assemblyName = "Some.Assembly.Name"
var nameSpace = "Some.Namespace.Name";
var className = "ClassNameFilter";

var asm = Assembly.Load(assemblyName);
var classes = asm.GetTypes().Where(p =>
     p.Namespace == nameSpace &&
     p.Name.Contains(className) 
).ToList();

注意:项目必须引用程序集

以下代码打印当前程序集中定义的指定名称空间中的类名称。 正如其他人指出的那样，名称空间可以分散在不同的模块之间，因此需要首先获得程序集列表。

string nspace = "...";

var q = from t in Assembly.GetExecutingAssembly().GetTypes()
        where t.IsClass && t.Namespace == nspace
        select t;
q.ToList().ForEach(t => Console.WriteLine(t.Name));

如果其中一个类型子类化了另一个程序集中的类型，你可能会发现LoaderException错误，下面是一个修复:

// Setup event handler to resolve assemblies
AppDomain.CurrentDomain.ReflectionOnlyAssemblyResolve += new ResolveEventHandler(CurrentDomain_ReflectionOnlyAssemblyResolve);

Assembly a = System.Reflection.Assembly.ReflectionOnlyLoadFrom(filename);
a.GetTypes();
// process types here

// method later in the class:
static Assembly CurrentDomain_ReflectionOnlyAssemblyResolve(object sender, ResolveEventArgs args)
{
    return System.Reflection.Assembly.ReflectionOnlyLoad(args.Name);
}

这应该有助于加载在其他程序集中定义的类型。

希望有帮助!

就像@aku的答案，但使用扩展方法:

string @namespace = "...";

var types = Assembly.GetExecutingAssembly().GetTypes()
    .Where(t => t.IsClass && t.Namespace == @namespace)
    .ToList();

types.ForEach(t => Console.WriteLine(t.Name));