以编程方式转发电子邮件消息（含内嵌图片）

• 下载源代码 - 28.2 KB

引言

这段示例代码对使用 VSTO 2005 程序化地转发带有内联图片的 Outlook 2007 电子邮件消息的开发人员来说非常有用。

背景

当我尝试使用 MailItem.Forward() 方法转发电子邮件时，由于我实现了自定义 Outlook 表单，所以它没有正常工作。而且，默认情况下，所选消息中的内联图片将作为附件添加到转发消息中。使用这段代码，您将获得一个解决方案，可以转发任何带有内联图片的电子邮件消息。

使用代码

在这个示例应用程序中，我遵循以下步骤：

1. 获取当前右键单击的电子邮件（所选电子邮件）。
2. 创建一个新的 Outlook 邮件（转发邮件）。
3. 将所选电子邮件的所需属性分配给转发邮件。
4. 修剪所选电子邮件的 HTMLBody 字符串，以便内联正文图片在转发邮件中显示为图片。（否则，所选电子邮件中的内联图片将作为附件添加到转发邮件中。）
5. 在新窗口中打开转发邮件。

下面显示了实现上述步骤的 ForwardSelectedMessage() 方法：

//
private void ForwardSelectedMessage()
{
    try
    {
        // create a new mail message 

        Outlook.MailItem ForwardingMessage = 
          (Outlook.MailItem)this.Application.CreateItem(
           Outlook.OlItemType.olMailItem);
        // In case you want to implement the custom outlook 
        // form you have use following commented 2 lines of code

        //Outlook.MAPIFolder templateFolder = 
        // this.Application.Session.GetDefaultFolder(
        //  Microsoft.Office.Interop.Outlook.OlDefaultFolders.olFolderInbox);

        //ForwardingMessage = (Outlook.MailItem)templateFolder.Items.Add(
        //                     "IPM.Note.OutlookCustomForm1");

        // get the currently selected message
        // (the message on which the user right-clicked)

        Outlook.MailItem SelectedMessage;
        SelectedMessage = (Outlook.MailItem)
          this.Application.ActiveExplorer().Selection[1];
        if (SelectedMessage != null)
        {
            if (ForwardingMessage != null)
            {
                //Subject 

                ForwardingMessage.Subject = "FW: " + SelectedMessage.Subject;
                #region Attahment 
                // Get the count of Attachments

                int attachCount = SelectedMessage.Attachments.Count;
                if (attachCount > 0)
                {
                    // loop through each attachment 

                    for (int idx = 1; idx <= attachCount; idx++)
                    {
                        string sysPath = System.IO.Path.GetTempPath();
                        if (!System.IO.Directory.Exists(sysPath + "~test"))
                        {
                            System.IO.Directory.CreateDirectory(sysPath + "~test");
                        }
                        // get attached file and save in temp folder

                        string strSourceFileName = sysPath + "~test\\" + 
                                       SelectedMessage.Attachments[idx].FileName;
                        SelectedMessage.Attachments[idx].SaveAsFile(strSourceFileName);
                        string strDisplayName = "Attachment";
                        int intPosition = 1;
                        int intAttachType = (int)Outlook.OlAttachmentType.olEmbeddeditem;
                        // Add the current attachment
                        ForwardingMessage.Attachments.Add(strSourceFileName, 
                                       intAttachType, intPosition, strDisplayName);
                    }
                }
                #endregion
                #region Body 
                string strHeader = "<p><br><br>" + 
                        "-----Original Message-----" + "<br>";
                strHeader += "From: " + SelectedMessage.SenderName + "<br>";
                strHeader += "Sent: " + SelectedMessage.SentOn.ToString() + "<br>";
                strHeader += "To: " + SelectedMessage.To + "<br>";
                strHeader += "Subject: " + SelectedMessage.Subject + "<br><br>";
                ForwardingMessage.HTMLBody = strHeader + 
                          GetTrimmedBodyText(SelectedMessage.HTMLBody);
                #endregion
                ForwardingMessage.Display(false);
            }
        }
    }
    catch (Exception ex)
    {
        if (ex.Message.ToLower().StartsWith("unable to cast com object"))
        {
            MessageBox.Show("This is not a valid message and it can not be sent.", 
                            "", MessageBoxButtons.OK, MessageBoxIcon.Information);
        }
        else
        {
            MessageBox.Show("ForwardSelectedMessage - " + ex.Message, 
                    "", MessageBoxButtons.OK, MessageBoxIcon.Error);
        }
    }
}
#region Handling inline images in the message body 
/* by defaule the inline images in the selected message
   will be added as attachments to the new message
   the reason is in htmlbody the image src will be as follows:
   src = "cid:image001.jpg@01C82869373A65B0"
   to view inline images (and avoid image attachments) it should changed as follows:
   src = "image001.jpg"
   replace "cid" with "" (empty string) and 
   replace "image001.jpg@01C82869373A65B0" with "image001.jpg" (only file name)
*/
private string GetTrimmedBodyText(string strHTMLBody)
{
    string strTrimmedHTMLBody = strHTMLBody;
    int start = 0;
    start = strHTMLBody.IndexOf("<img", start);
    /* the following loop will check for each src attribute value for each image and 
       it will replace them only with image file name (by removing cid: and @ part)
    */
    while (start > 0)
    {
        int count = strHTMLBody.IndexOf('>', start);
        string str = strHTMLBody.Substring(start);
        string strActualImgTag = str.Substring(0, str.IndexOf(">") + 1);
        string strTrimImgTag = strActualImgTag.Replace("cid:", "");
        int intAtPosition = 0;
        intAtPosition = strTrimImgTag.IndexOf("@");
        while (intAtPosition > 0)
        {
            string strAt = 
              strTrimImgTag.Substring(strTrimImgTag.IndexOf("@"), 18);
            strTrimImgTag = strTrimImgTag.Replace(strAt, "");
            intAtPosition = strTrimImgTag.IndexOf("@");
        }
        strTrimmedHTMLBody = 
          strTrimmedHTMLBody.Replace(strActualImgTag, strTrimImgTag);
        start = strHTMLBody.IndexOf("<img", start + 1);
    }
    return strTrimmedHTMLBody;
}
#endregion
#endregion
//