检索类型Foo <Bar> 从TypeBuilder创建Bar时从名称开始

Question

我正在使用TypeBuilder创建类型。 然后将这些类型用作通用类中的参数。 我要做的是从名称创建Type 。 通用参数是动态的，这似乎是一个障碍。

static public class DynamicTypeTest
{
    public class Generic<T> { }

    static public void Test()
    {
        Type dynamicType = createDynamicType();
        Type genericType = typeof(Generic<>);

        // Generic<DynamicType>
        Type genericDynamicType = genericType.MakeGenericType(new Type[]{dynamicType});

        Debug.Assert(TypeFromName(genericDynamicType.FullName) == genericDynamicType);              // fail
        Debug.Assert(TypeFromName(genericDynamicType.AssemblyQualifiedName) == genericDynamicType); // fail
        Debug.Assert(TypeFromName(genericDynamicType.Name) == genericDynamicType);                  // fail

        // Generic<int>
        Type genericIntType = genericType.MakeGenericType(new Type[] { typeof(int) });

        Debug.Assert(TypeFromName(genericIntType.FullName) == genericIntType); // This succeeds. Replacing 'int' with a Type defined in another project also works
    }

    // This is the essence of what I want to do
    static private Type TypeFromName(string name)
    {
        return Assembly.GetExecutingAssembly().GetType(name);
    }

    static private Type createDynamicType()
    {
        AssemblyName assemblyName = new AssemblyName("DynamicAssembly");
        AssemblyBuilder assemblyBuilder = AppDomain.CurrentDomain.DefineDynamicAssembly(assemblyName, AssemblyBuilderAccess.Run);
        ModuleBuilder moduleBuilder = assemblyBuilder.DefineDynamicModule("DynamicModule");
        TypeAttributes typeAttributes = TypeAttributes.Public | TypeAttributes.Class | TypeAttributes.AutoClass | TypeAttributes.AnsiClass;
        TypeBuilder typeBuilder = moduleBuilder.DefineType("DynamicType", typeAttributes, typeof(System.Object));

        return typeBuilder.CreateType();
    }
}

显然，我知道如何从MakeGenericType创建Type ，但是在我正在使用的实际场景中，我不想（或不能）修改类型名称，以便我可以分别创建类型并将它们拼凑起来一起。

如何从string名称重新创建这种Type ？

Answer 1

我想到我应该使用Assembly.GetType()的版本，该版本在错误时引发Exception 。 它引发了FileNotFoundException ，因此很显然，在通用参数中，仅允许文件中的程序集。 为了解决这个问题，我从AppDomain注册了AssemblyResolve事件，并处理了在文件上找不到DynamicAssembly的情况。 我的工作代码：

static public class DynamicTypeTest
{
    public class Generic<T> { }

    static public void Test()
    {
        AppDomain.CurrentDomain.AssemblyResolve += CurrentDomain_AssemblyResolve;

        Type dynamicType = createDynamicType();
        Type genericType = typeof(Generic<>);

        // Generic<DynamicType>
        Type genericDynamicType = genericType.MakeGenericType(new Type[]{dynamicType});

        Debug.Assert(TypeFromName(genericDynamicType.FullName) == genericDynamicType); // pass

        AppDomain.CurrentDomain.AssemblyResolve -= CurrentDomain_AssemblyResolve;
    }

    static Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args)
    {
        foreach (Assembly assembly in AppDomain.CurrentDomain.GetAssemblies())
        {
            AssemblyName assemblyName = assembly.GetName();

            if (args.Name == assemblyName.FullName)
            {
                return assembly;
            }
        }

        return null;
    }

    // This is the essence of what I want to do
    static private Type TypeFromName(string name)
    {
        try
        {
            return typeof(Generic<>).Assembly.GetType(name, true);
        }
        catch (Exception)
        {
            return null;
        }
    }

    static private Type createDynamicType()
    {
        AssemblyName assemblyName = new AssemblyName("DynamicAssembly");
        AssemblyBuilder assemblyBuilder = AppDomain.CurrentDomain.DefineDynamicAssembly(assemblyName, AssemblyBuilderAccess.Run);
        ModuleBuilder moduleBuilder = assemblyBuilder.DefineDynamicModule("DynamicModule");
        TypeAttributes typeAttributes = TypeAttributes.Public | TypeAttributes.Class | TypeAttributes.AutoClass | TypeAttributes.AnsiClass;
        TypeBuilder typeBuilder = moduleBuilder.DefineType("DynamicType", typeAttributes, typeof(System.Object));

        return typeBuilder.CreateType();
    }