我的问题是我需要使用 C# 将文件附加到默认邮件客户端并将其显示给用户，就像使用mailto:.
我阅读了有关该主题的这篇文章，但有几个问题：
mailto，因为附件不受官方支持。那么，对于这个问题还有其他简单的解决方案吗？是否有另一种简单的方法来弹出带有预填充.NET 附件的默认邮件客户端？也许是另一个 MAPI 包装器，但是一个具有非常宽松的许可证？
如果您对未嵌入的附件感到满意，这里有很多代码可以完成这项工作。这对于可能来寻找的其他人来说比我确信必须已经找到替代方案的 OP 更重要。如果缺少某些内容，请添加评论，我将添加必要的内容。享受！
public class MailMessage
{
#region Constants and Fields
private readonly string _body;
private readonly string _subject;
private readonly List<MapiFileDesc> _attachments;
private readonly List<MapiRecipDesc> _recipients;
#endregion
#region Constructors and Destructors
private MailMessage()
{
}
public MailMessage(
string subject, string body, IEnumerable<MailAttachment> attachments, IEnumerable<MailRecipient> recipients)
{
this._subject = subject;
this._body = body;
this._attachments = new List<MapiFileDesc>();
this._recipients = new List<MapiRecipDesc>();
if (attachments != null)
{
foreach (var attachment in attachments)
{
_attachments.Add(attachment.GetMapiFileDesc());
}
}
if (recipients != null)
{
foreach (var recipient in recipients)
{
_recipients.Add(recipient.GetMapiRecipDesc());
}
}
}
#endregion
#region Public Methods
public void ShowDialog()
{
int result = this.ShowMail();
if (!IsSuccess(result))
{
throw new Exception(GetMapiErrorMessage(result));
}
}
#endregion
#region Methods
private int ShowMail()
{
var message = new MapiMessage();
message.Subject = this._subject;
message.NoteText = this._body;
int attachmentCount;
message.Files = AllocMapiDescArray(_attachments, out attachmentCount);
message.FileCount = attachmentCount;
int recipientCount;
message.Recipients = AllocMapiDescArray(_recipients, out recipientCount);
message.RecipientCount = recipientCount;
int error = Mapi32.MAPISendMail(IntPtr.Zero, IntPtr.Zero, message, Mapi32.MAPI_DIALOG, 0);
DeallocMapiDescArray<MapiFileDesc>(message.Files, message.FileCount);
DeallocMapiDescArray<MapiRecipDesc>(message.Recipients, message.RecipientCount);
return error;
}
private static IntPtr AllocMapiDescArray<T>(ICollection<T> mapiDescCollection, out int mapiDescCount)
{
IntPtr mapiMapiDescArrayPtr = IntPtr.Zero;
mapiDescCount = 0;
if (mapiDescCollection != null && mapiDescCollection.Count > 0)
{
int mapiDescSize = Marshal.SizeOf(typeof(T));
mapiMapiDescArrayPtr = Marshal.AllocHGlobal(mapiDescCollection.Count * mapiDescSize);
var tmp = (int)mapiMapiDescArrayPtr;
foreach (var mapiDesc in mapiDescCollection)
{
Marshal.StructureToPtr(mapiDesc, (IntPtr)tmp, false);
tmp += mapiDescSize;
}
mapiDescCount = mapiDescCollection.Count;
}
return mapiMapiDescArrayPtr;
}
private static void DeallocMapiDescArray<T>(IntPtr mapiDescArrayPtr, int mapiDescArrayCount)
{
if (mapiDescArrayPtr != IntPtr.Zero)
{
int mapiDescSize = Marshal.SizeOf(typeof(T));
var tmp = (int)mapiDescArrayPtr;
for (int i = 0; i < mapiDescArrayCount; i++)
{
Marshal.DestroyStructure((IntPtr)tmp, typeof(T));
tmp += mapiDescSize;
}
Marshal.FreeHGlobal(mapiDescArrayPtr);
}
}
private static bool IsSuccess(int errorCode)
{
return (errorCode == Mapi32.SUCCESS_SUCCESS || errorCode == Mapi32.MAPI_USER_ABORT);
}
private static string GetMapiErrorMessage(int errorCode)
{
// This should be localized
string error = string.Empty;
switch (errorCode)
{
case Mapi32.MAPI_USER_ABORT:
error = "User Aborted.";
break;
case Mapi32.MAPI_E_FAILURE:
error = "MAPI Failure.";
break;
case Mapi32.MAPI_E_LOGIN_FAILURE:
error = "Login Failure.";
break;
case Mapi32.MAPI_E_DISK_FULL:
error = "MAPI Disk full.";
break;
case Mapi32.MAPI_E_INSUFFICIENT_MEMORY:
error = "MAPI Insufficient memory.";
break;
case Mapi32.MAPI_E_BLK_TOO_SMALL:
error = "MAPI Block too small.";
break;
case Mapi32.MAPI_E_TOO_MANY_SESSIONS:
error = "MAPI Too many sessions.";
break;
case Mapi32.MAPI_E_TOO_MANY_FILES:
error = "MAPI too many files.";
break;
case Mapi32.MAPI_E_TOO_MANY_RECIPIENTS:
error = "MAPI too many recipients.";
break;
case Mapi32.MAPI_E_ATTACHMENT_NOT_FOUND:
error = "MAPI Attachment not found.";
break;
case Mapi32.MAPI_E_ATTACHMENT_OPEN_FAILURE:
error = "MAPI Attachment open failure.";
break;
case Mapi32.MAPI_E_ATTACHMENT_WRITE_FAILURE:
error = "MAPI Attachment Write Failure.";
break;
case Mapi32.MAPI_E_UNKNOWN_RECIPIENT:
error = "MAPI Unknown recipient.";
break;
case Mapi32.MAPI_E_BAD_RECIPTYPE:
error = "MAPI Bad recipient type.";
break;
case Mapi32.MAPI_E_NO_MESSAGES:
error = "MAPI No messages.";
break;
case Mapi32.MAPI_E_INVALID_MESSAGE:
error = "MAPI Invalid message.";
break;
case Mapi32.MAPI_E_TEXT_TOO_LARGE:
error = "MAPI Text too large.";
break;
case Mapi32.MAPI_E_INVALID_SESSION:
error = "MAPI Invalid session.";
break;
case Mapi32.MAPI_E_TYPE_NOT_SUPPORTED:
error = "MAPI Type not supported.";
break;
case Mapi32.MAPI_E_AMBIGUOUS_RECIPIENT:
error = "MAPI Ambiguous recipient.";
break;
case Mapi32.MAPI_E_MESSAGE_IN_USE:
error = "MAPI Message in use.";
break;
case Mapi32.MAPI_E_NETWORK_FAILURE:
error = "MAPI Network failure.";
break;
case Mapi32.MAPI_E_INVALID_EDITFIELDS:
error = "MAPI Invalid edit fields.";
break;
case Mapi32.MAPI_E_INVALID_RECIPS:
error = "MAPI Invalid Recipients.";
break;
case Mapi32.MAPI_E_NOT_SUPPORTED:
error = "MAPI Not supported.";
break;
case Mapi32.MAPI_E_NO_LIBRARY:
error = "MAPI No Library.";
break;
case Mapi32.MAPI_E_INVALID_PARAMETER:
error = "MAPI Invalid parameter.";
break;
}
return string.Format("Error sending email. Error: {0} (code = {1}).", error, errorCode);
}
#endregion
}
public class MailAttachment
{
private string _attachmentFilePath;
public MailAttachment(string attachmentFilePath)
{
_attachmentFilePath = attachmentFilePath;
}
public MapiFileDesc GetMapiFileDesc()
{
var mapiFileDesc = new MapiFileDesc();
mapiFileDesc.Position = -1;
mapiFileDesc.Path = _attachmentFilePath;
mapiFileDesc.Name = Path.GetFileName(_attachmentFilePath);
return mapiFileDesc;
}
}
public class MailRecipient
{
#region Constants and Fields
public string _emailAddress;
public string _displayName;
public MailRecipientType _mailRecipientType = MailRecipientType.To;
#endregion
#region Constructors and Destructors
public MailRecipient(string emailAddress, string displayName, MailRecipientType mailRecipientType)
{
this._emailAddress = emailAddress;
this._displayName = displayName;
this._mailRecipientType = mailRecipientType;
}
#endregion
#region Methods
public MapiRecipDesc GetMapiRecipDesc()
{
var recipDesc = new MapiRecipDesc();
if (this._displayName == null)
{
recipDesc.Name = this._emailAddress;
}
else
{
recipDesc.Name = this._displayName;
recipDesc.Address = this._emailAddress;
}
recipDesc.RecipientClass = (int)this._mailRecipientType;
return recipDesc;
}
#endregion
}
public enum MailRecipientType
{
To = 1,
CC = 2,
BCC = 3
} ;
internal class Mapi32
{
#region Constants and Fields
public const int MAPI_DIALOG = 0x8;
public const int MAPI_E_AMBIGUOUS_RECIPIENT = 21;
public const int MAPI_E_ATTACHMENT_NOT_FOUND = 11;
public const int MAPI_E_ATTACHMENT_OPEN_FAILURE = 12;
public const int MAPI_E_ATTACHMENT_WRITE_FAILURE = 13;
public const int MAPI_E_BAD_RECIPTYPE = 15;
public const int MAPI_E_BLK_TOO_SMALL = 6;
public const int MAPI_E_DISK_FULL = 4;
public const int MAPI_E_FAILURE = 2;
public const int MAPI_E_INSUFFICIENT_MEMORY = 5;
public const int MAPI_E_INVALID_EDITFIELDS = 24;
public const int MAPI_E_INVALID_MESSAGE = 17;
public const int MAPI_E_INVALID_PARAMETER = 998;
public const int MAPI_E_INVALID_RECIPS = 25;
public const int MAPI_E_INVALID_SESSION = 19;
public const int MAPI_E_LOGIN_FAILURE = 3;
public const int MAPI_E_MESSAGE_IN_USE = 22;
public const int MAPI_E_NETWORK_FAILURE = 23;
public const int MAPI_E_NOT_SUPPORTED = 26;
public const int MAPI_E_NO_LIBRARY = 999;
public const int MAPI_E_NO_MESSAGES = 16;
public const int MAPI_E_TEXT_TOO_LARGE = 18;
public const int MAPI_E_TOO_MANY_FILES = 9;
public const int MAPI_E_TOO_MANY_RECIPIENTS = 10;
public const int MAPI_E_TOO_MANY_SESSIONS = 8;
public const int MAPI_E_TYPE_NOT_SUPPORTED = 20;
public const int MAPI_E_UNKNOWN_RECIPIENT = 14;
public const int MAPI_LOGON_UI = 0x1;
public const int MAPI_USER_ABORT = 1;
public const int SUCCESS_SUCCESS = 0;
#endregion
#region Public Methods
[DllImport("MAPI32.DLL", CharSet = CharSet.Ansi)]
public static extern int MAPILogon(IntPtr hwnd, string prf, string pw, int flg, int rsv, ref IntPtr sess);
[DllImport("MAPI32.DLL")]
public static extern int MAPISendMail(IntPtr session, IntPtr hwnd, MapiMessage message, int flg, int rsv);
#endregion
}
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public class MapiFileDesc
{
public int Reserved;
public int Flags;
public int Position;
public string Path;
public string Name;
public IntPtr Type = IntPtr.Zero;
}
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public class MapiMessage
{
public int Reserved;
public string Subject;
public string NoteText;
public string MessageType;
public string DateReceived;
public string ConversationID;
public int Flags;
public IntPtr Originator = IntPtr.Zero;
public int RecipientCount;
public IntPtr Recipients = IntPtr.Zero;
public int FileCount;
public IntPtr Files = IntPtr.Zero;
}
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public class MapiRecipDesc
{
public int Reserved;
public int RecipientClass;
public string Name;
public string Address;
public int eIDSize;
public IntPtr EntryID = IntPtr.Zero;
}
.NET mapi wrapper 确实是最好的解决方案 - 谷歌“mapi .net wrapper”返回了许多结果，我相信其中一个将具有合适的许可证：