/// <summary>
/// Creates and sends an e-mail message using the Simple MAPI protocol.</summary>
/// <param name="subject">
/// The subject line of the e-mail message.</param>
/// <param name="noteText">
/// The text of the e-mail message.</param>
/// <param name="recipients">
/// An <see cref="Array"/> of <see cref="MapiAddress"/> instances holding the display names
/// and SMTP addresses of all message recipients. The protocol identifier "smtp:" is
/// automatically prepended to any non-empty addresses without this prefix.</param>
/// <param name="attachments">
/// An <see cref="Array"/> of <see cref="MapiAddress"/> instances holding the display names
/// and fully qualified local file paths of any attachment files sent to the <paramref
/// name="recipients"/>.</param>
/// <exception cref="MapiException">
/// <see cref="Mapi.MAPISendMail"/> indicated an error.</exception>
/// <remarks><para>
/// <b>SendMail</b> creates and sends an e-mail message with optional file attachments,
/// using the Win32 API call <see cref="Mapi.MAPISendMail"/> which is part of the Simple
/// MAPI protocol. The originator is left undefined which will cause Simple MAPI to assert
/// the user’s default e-mail account as the originator.
/// </para><para>
/// The <paramref name="subject"/> and <paramref name="noteText"/> parameters may be a null
/// reference or an empty string to leave the corresponding field blank. The <paramref
/// name="recipients"/> and <paramref name="attachments"/> parameters may be null references
/// or empty arrays to create a message without recipients or file attachments,
/// respectively.
/// </para><para>
/// The e-mail message is presented to the user who can choose to edit (filling in any blank
/// fields or adding text as desired), send, or cancel the message. User cancellation
/// generates a <see cref="MapiException"/> whose <see cref="MapiException.Code"/> is <see
/// cref="MapiException.Abort"/>.</para></remarks>
public static void SendMail(string subject, string noteText,
MapiAddress[] recipients, MapiAddress[] attachments)
{
// remember current working directory
string currentDir = Directory.GetCurrentDirectory();
// construct MAPI message descriptor
MapiMessage message = new MapiMessage();
message.lpszSubject = subject;
message.lpszNoteText = noteText;
try {
// create any specified recipients
if (recipients != null && recipients.Length > 0)
{
// store count of recipient descriptors
int count = recipients.Length;
message.nRecipCount = (uint)count;
// allocate memory for recipient descriptors
int size = Marshal.SizeOf(typeof(MapiRecipDesc));
message.lpRecips.AllocateHandle(count * size);
// construct recipient descriptors
MapiRecipDesc recip = new MapiRecipDesc();
for (int i = 0; i < count; i++)
{
// prepend "smtp:" to address if not present
string address = recipients[i].Address;
if (!String.IsNullOrEmpty(address) &&
!address.StartsWith("smtp:", StringComparison.OrdinalIgnoreCase))
{
address = "smtp:" + address;
}
// create MAPI recipient descriptor
recip.ulRecipClass = MapiRecipClass.MAPI_TO;
recip.lpszName = recipients[i].Name;
recip.lpszAddress = address;
// copy recipient descriptor to unmanaged memory
message.lpRecips.SetMemory(recip, i * size, false);
}
}
// create any specified attachments
if (attachments != null && attachments.Length > 0)
{
// store count of attachment descriptors
int count = attachments.Length;
message.nFileCount = (uint)count;
// allocate memory for attachment descriptors
int size = Marshal.SizeOf(typeof(MapiFileDesc));
message.lpFiles.AllocateHandle(count * size);
// construct attachment descriptors
MapiFileDesc fileDesc = new MapiFileDesc();
for (int i = 0; i < count; i++)
{
// create MAPI file attachment descriptor
fileDesc.lpszFileName = attachments[i].Name;
fileDesc.lpszPathName = attachments[i].Address;
fileDesc.nPosition = 0xffffffff; // don’t embed files
// copy attachment descriptor to unmanaged memory
message.lpFiles.SetMemory(fileDesc, i * size, false);
}
}
// invoke MAPISendMail to deliver this message
MapiFlags flags = MapiFlags.MAPI_DIALOG | MapiFlags.MAPI_LOGON_UI;
MapiError code = Mapi.MAPISendMail(UIntPtr.Zero, UIntPtr.Zero, message, flags, 0);
// throw exception if MAPI reports failure
if (code != MapiError.SUCCESS_SUCCESS)
{
ThrowMapiException(code);
}
}
finally {
// release unmanaged memory blocks
message.Dispose();
// restore original working directory
Directory.SetCurrentDirectory(currentDir);
}
}