如何通过 COM4J 从 C# 方法将对象数组(实现 COM 接口)返回到 Java 方法?
生成数组的示例 C# 类:
using System;
using System.Runtime.InteropServices;
namespace Example
{
[ComVisible(true), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IAnimal
{
string Speak();
}
[ComVisible(true), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IFarm
{
[return:MarshalAs(UnmanagedType.SafeArray,
SafeArraySubType=VarEnum.VT_UNKNOWN)]
IAnimal[] GetAnimals();
}
[ComVisible(true), ClassInterface(ClassInterfaceType.None)]
public class Farm : IFarm
{
public IAnimal[] GetAnimals()
{
return new IAnimal[] { new Cow(), new Pig() };
}
}
internal class Cow: IAnimal
{
public string Speak()
{
return "Moo";
}
}
internal class Pig: IAnimal
{
public string Speak()
{
return "Oink";
}
}
}
生成的 .tlb 中的接口声明如下所示:
[
odl,
uuid(1FB5E376-E78D-3A2E-BEF3-F3C798FCF44C),
version(1.0),
oleautomation,
custom(0F21F359-AB84-41E8-9A78-36D110E6D2F9, "Example.IFarm")
]
interface IFarm : IUnknown
{
HRESULT _stdcall GetAnimals([out, retval] SAFEARRAY(IUnknown*)* pRetVal);
};
Java客户端代码:
import com4j.*;
public class Example {
public static void main(String[] args) {
IFarm farm = ClassFactory.createFarm();
Com4jObject[] animals = farm.getAnimals();
for (Com4jObject o: animals) {
IAnimal animal = o.queryInterface(IAnimal.class);
if (animal != null) {
animal.speak();
}
}
}
}
这可以编译,但我在运行时得到这个异常:
Exception in thread "main" com4j.ComException:
unexpected conversion type: 500 : .\invoke.cpp:470
at com4j.Wrapper.invoke(Wrapper.java:185)
at $Proxy5.getAnimals(Unknown Source)
at MainClass.main(MainClass.java:7)
Caused by: com4j.ComException: unexpected conversion type: 500 : .\invoke.cpp:470
at com4j.Native.invoke(Native Method)
at com4j.StandardComMethod.invoke(StandardComMethod.java:35)
at com4j.Wrapper$InvocationThunk.call(Wrapper.java:354)
at com4j.Task.invoke(Task.java:55)
at com4j.ComThread.run0(ComThread.java:157)
at com4j.ComThread.run(ComThread.java:137)
我尝试过的其他事情:
- 编组为 a
SAFEARRAY(VARIANT)*
而不是SAFEARRAY(IUnknown*)*
(这会引发相同的异常。) - 删除
MarshalAs
属性(tlbimp
创建代理方法失败)
有没有办法编组数组以便 COM4J 可以将其转换为有效的 Java 数组?
或者,有没有办法在 Java 中分配一个数组并允许 .NET 方法填充它?(我试过了,但是 .NET 方法接收到数组的副本,Java 代码永远不会看到插入到副本中的对象。也许有办法覆盖它?)
编辑:这可能是相关的:https ://stackoverflow.com/a/6340144/12048 - 类似的东西似乎可以从 VBScript