C++/CLI 如何封装VB.NET中使用的带结构体的Windows 的API，在VB.NET中调用封装后的Api，详细例子

首先，需要编写 C++/CLI 封装带结构体的 Windows API，然后在 VB.NET 中调用该封装后的 API。

以下是一个简单的例子，演示如何封装 `CreateFile` 函数：

C++/CLI 封装：

#pragma once

#include <Windows.h>

using namespace System;
using namespace System::Runtime::InteropServices;

namespace MyAPIWrapper
{
    public ref class FileHandleWrapper
    {
    public:
        property IntPtr Handle
        {
            IntPtr get() { return m_handle; }
        }

        FileHandleWrapper(String^ fileName, FileMode mode, FileAccess access)
        {
            pin_ptr<const wchar_t> pFileName = PtrToStringChars(fileName);
            DWORD dwDesiredAccess = 0;
            DWORD dwCreationDisposition = 0;

            switch (access)
            {
            case FileAccess::Read:
                dwDesiredAccess = GENERIC_READ;
                break;
            case FileAccess::Write:
                dwDesiredAccess = GENERIC_WRITE;
                break;
            case FileAccess::ReadWrite:
                dwDesiredAccess = GENERIC_READ | GENERIC_WRITE;
                break;
            }

            switch (mode)
            {
            case FileMode::Create:
                dwCreationDisposition = CREATE_ALWAYS;
                break;
            case FileMode::Open:
                dwCreationDisposition = OPEN_EXISTING;
                break;
            }

            m_handle = CreateFile(pFileName, dwDesiredAccess, 0, NULL, dwCreationDisposition, 0, NULL);
        }

        ~FileHandleWrapper()
        {
            CloseHandle(m_handle);
        }

    private:
        IntPtr m_handle;
    };
}

VB.NET 调用：

Imports System.IO
Imports MyAPIWrapper

Public Class Form1

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim fileName As String = "test.txt"
        Dim mode As FileMode = FileMode.Create
        Dim access As FileAccess = FileAccess.Write

        Using fh As New FileHandleWrapper(fileName, mode, access)
            Using sw As New StreamWriter(New FileStream(fh.Handle, FileAccess.Write))
                sw.WriteLine("Hello, world!")
            End Using
        End Using
    End Sub

End Class

在 VB.NET 中，我们可以像使用普通的文件句柄一样使用封装后的 `FileHandleWrapper` 类，这样可以避免直接调用 Windows API 带来的一些问题，同时也方便了 VB.NET 开发人员的使用。