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));

using System.Reflection;
using System.Collections.Generic;
//...

static List<string> GetClasses(string nameSpace)
{
    Assembly asm = Assembly.GetExecutingAssembly();

    List<string> namespacelist = new List<string>();
    List<string> classlist = new List<string>();

    foreach (Type type in asm.GetTypes())
    {
        if (type.Namespace == nameSpace)
            namespacelist.Add(type.Name);
    }

    foreach (string classname in namespacelist)
        classlist.Add(classname);

    return classlist;
}

注:上面的代码说明了发生了什么。如果你要实现它，可以使用一个简化版本:

using System.Linq;
using System.Reflection;
using System.Collections.Generic;
//...

static IEnumerable<string> GetClasses(string nameSpace)
{
    Assembly asm = Assembly.GetExecutingAssembly();
    return asm.GetTypes()
        .Where(type => type.Namespace == nameSpace)
        .Select(type => type.Name);
}

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()

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()。

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!

//a simple combined code snippet 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Reflection;

namespace MustHaveAttributes
{
  class Program
  {
    static void Main ( string[] args )
    {
      Console.WriteLine ( " START " );

      // what is in the assembly
      Assembly a = Assembly.Load ( "MustHaveAttributes" );
      Type[] types = a.GetTypes ();
      foreach (Type t in types)
      {

        Console.WriteLine ( "Type is {0}", t );
      }
      Console.WriteLine (
         "{0} types found", types.Length );

      #region Linq
      //#region Action


      //string @namespace = "MustHaveAttributes";

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


      //#endregion Action  
      #endregion

      Console.ReadLine ();
      Console.WriteLine ( " HIT A KEY TO EXIT " );
      Console.WriteLine ( " END " );
    }
  } //eof Program


  class ClassOne
  {

  } //eof class 

  class ClassTwo
  {

  } //eof class


  [System.AttributeUsage ( System.AttributeTargets.Class |
    System.AttributeTargets.Struct, AllowMultiple = true )]
  public class AttributeClass : System.Attribute
  {

    public string MustHaveDescription { get; set; }
    public string MusHaveVersion { get; set; }


    public AttributeClass ( string mustHaveDescription, string mustHaveVersion )
    {
      MustHaveDescription = mustHaveDescription;
      MusHaveVersion = mustHaveVersion;
    }

  } //eof class 

} //eof namespace