在COM中从c#返回对象数组到C

return array of object from C# to C in COM

本文关键字：数组对象返回 COM 中从更新时间：2023-10-16

我使用COM在c++和c#之间进行通信。

我在c#中有以下类

电子邮件地址

/// <summary>
/// Email Address
/// </summary>
public class EmailAddress
{
    /// <summary>
    /// SMTP Address
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]        
    public string Address;
    /// <summary>
    /// Name
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string Name;
}

/// <summary>
/// MailBox Entity
/// </summary>   
public struct MailBoxEntity
{
    /// <summary>
    /// SMTP Address
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string SMTPAddress;
    /// <summary>
    /// Mailbox Display Name
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string Name;
    /// <summary>
    /// Mailbox Server Name
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string sServerName;
}

EmailEntity(尚未实现IEmailEntity，它将包含每个字段的属性)

/// <summary>
/// Class for Email Entity
/// </summary>
public class EmailEntity : IEmailEntity
{
    /// <summary>
    /// BccRecipients
    /// </summary>
    [MarshalAs(UnmanagedType.ByValArray)]
    public EmailAddress[] BccRecipients;
    /// <summary>
    /// Body
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string Body;
    /// <summary>
    /// CcRecipients
    /// </summary>
    [MarshalAs(UnmanagedType.ByValArray)]
    public EmailAddress[] CcRecipients;
    /// <summary>
    /// Culture
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string Culture;
    /// <summary>
    /// DateTimeCreated
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string DateTimeCreated;
    /// <summary>
    /// DateTimeReceived
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string DateTimeReceived;
    /// <summary>
    /// DateTimeSent
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string DateTimeSent;
    /// <summary>
    /// FromAddress
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string FromAddress;
    /// <summary>
    /// FromName
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string FromName;

    /// <summary>
    /// HasAttachments
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string HasAttachments;
    /// <summary>
    /// Id
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string Id;
    /// <summary>
    /// Importance
    /// </summary>
   [MarshalAs(UnmanagedType.BStr)]
    public string Importance;
    /// <summary>
    /// LastModifiedName
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string LastModifiedName;
    /// <summary>
    /// LastModifiedTime
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string LastModifiedTime;
    /// <summary>
    /// MimeContent
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string MimeContent;
    /// <summary>
    /// ParentFolderId
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string ParentFolderId;
    /// <summary>
    /// Original Mailbox
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public MailBoxEntity OriginalMailBox;

    /// <summary>
    /// ParentFolderName
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string ParentFolderName;
    /// <summary>
    /// ReceivedByAddress
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string ReceivedByAddress;
    /// <summary>
    /// ReceivedByName
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string ReceivedByName;
    /// <summary>
    /// Size
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string Size;
    /// <summary>
    /// Subject
    /// </summary>
    [MarshalAs(UnmanagedType.BStr)]
    public string Subject;
    /// <summary>
    /// ToRecipients
    /// </summary>
    [MarshalAs(UnmanagedType.ByValArray)]
    public EmailAddress[] ToRecipients;
}

我如何访问访问一个数组的EmailEnity对象(在c++中)返回从一个函数在c#读取EmailEntity类的字段。请注意，EmailEntity类包含如下成员EmailAddress[]本身是一个对象数组。我计划实现接口IEmailEntity，它包含访问EmailEntity字段的属性并使用它来访问c++中的字段。这是正确的方式吗?

如何在c++中访问复杂的字段成员，如EmailAddress (EmailAddress[] toreceivers)数组。

请建议。

谢谢

你可以这样简化。net代码(删除所有应该自动完成的MarshalAs):

[ComVisible(true)]
public class MyRootClass : IMyRootClass // some class to start with
{
    public IEmailEntity[] GetEntities()
    {
        List<IEmailEntity> list = new List<IEmailEntity>();
        for(int i = 0; i < 10; i++)
        {
            EmailEntity entity = new EmailEntity();
            List<IEmailAddress> addresses = new List<IEmailAddress>();
            addresses.Add(new EmailAddress { Name = "Joe" + i });
            entity.BccRecipients = addresses.ToArray();
            entity.Body = "hello world " + i;
            list.Add(entity);
        }
        return list.ToArray();
    }   
}
[ComVisible(true)]
public interface IMyRootClass
{
    IEmailEntity[] GetEntities();
}
public class EmailEntity : IEmailEntity
{
    public IEmailAddress[] BccRecipients { get; set; }
    public string Body { get; set; }
}
public class EmailAddress : IEmailAddress
{
    public string Address { get; set; }
    public string Name { get; set; }
}
[ComVisible(true)]
public interface IEmailAddress
{
    string Address { get; set; }
    string Name { get; set; }
}
[ComVisible(true)]
public interface IEmailEntity
{
    IEmailAddress[] BccRecipients { get; set; }
    string Body { get; set; }
    // to be continued...
}

要在c++中使用它，您需要注册DLL并构建一个。tlb(类型库文件)，正如这里类似的答案所解释的那样:在非托管c++程序中实现c# DLL COM文件

然后，你可以在c++中访问这些类，像这样:

#include "stdafx.h"
#import  "c:MyPathToTheTlbYourAssembly.tlb" // import the COM TLB
using namespace YourAssembly;
int _tmain(int argc, _TCHAR* argv[])
{
  CoInitialize(NULL);
  IMyRootClassPtr ptr(__uuidof(MyRootClass));
  CComSafeArray<IUnknown*> entities = ptr->GetEntities(); // CComSafeArray needs atlsafe.h in the PCH
  for(int i = entities.GetLowerBound(0); i <= entities.GetUpperBound(0); i++)
  {
    IEmailEntityPtr entity;
    entities.GetAt(i).QueryInterface(&entity);
    _bstr_t body = entity->Body;
    printf("%Sn", body.GetBSTR());
    CComSafeArray<IUnknown*> recipients = entity->BccRecipients;
    for(int j = recipients.GetLowerBound(0); j <= recipients.GetUpperBound(0); j++)
    {
      IEmailAddressPtr address;
      recipients.GetAt(j).QueryInterface(&address);
      _bstr_t name = address->Name;
      printf(" %Sn", name.GetBSTR());
    }
  }
  CoUninitialize();
}