通过 COM 可见 DLL 从 VB6 调用 .NET 方法

问题描述：

我创建了一个 .NET DLL，它使某些方法 COM 可见.

I have created a .NET DLL which makes some methods COM visible.

一种方法有问题.它看起来像这样:

One method is problematic. It looks like this:

bool Foo(byte[] a, ref byte[] b, string c, ref string d)

当我尝试调用该方法时，VB6 出现编译错误:

VB6 gives a compile error when I attempt to call the method:

函数或接口标记为受限，或者函数使用不支持自动化类型Visual Basic.

Function or interface marked as restricted, or the function uses an Automation type not supported in Visual Basic.

我读到数组参数必须通过引用传递，所以我修改了签名中的第一个参数:

I read that array parameters must be passed by reference, so I altered the first parameter in the signature:

bool Foo(ref byte[] a, ref byte[] b, string c, ref string d)

VB6 仍然给出相同的编译错误.

VB6 still gives the same compile error.

我如何更改签名以与 VB6 兼容?

How might I alter the signature to be compatible with VB6?

答

需要使用ref"声明数组参数.您的第二次尝试应该可以正常工作，也许您忘记重新生成 .tlb?

Declaring the array argument with "ref" is required. Your 2nd attempt should have worked just fine, perhaps you forgot to regenerate the .tlb?

测试代码:

[ComVisible(true)]
public interface IMyInterface {
 bool Foo(ref byte[] a, ref byte[] b,string c, ref string d);
}

[ComVisible(true)]
public class MyClass : IMyInterface {
  public bool Foo(ref byte[] a, ref byte[] b, string c, ref string d) {
    throw new NotImplementedException();
  }
}


  Dim obj As ClassLibrary10.IMyInterface
  Set obj = New ClassLibrary10.MyClass
  Dim binp() As Byte
  Dim bout() As Byte
  Dim sinp As String
  Dim sout As String
  Dim retval As Boolean
  retval = obj.Foo(binp, bout, sinp, sout)

通过 COM 可见 DLL 从 VB6 调用 .NET 方法

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