利用Sharepoint指定From发送邮件

protected void bt_SendMail_Click(object sender, EventArgs e)
        {
            string result = sendSalaryMail();
            lbResult.Text = result;
        }

        private string sendSalaryMail()
        {
            #region varian
            StringBuilder sbResult = new StringBuilder();
            string tmpId = tb_TempId.Text;
            string emailFrom = string.Empty;
            string emailTitle = string.Empty;
            string emailBody = string.Empty;
            string folderPath = string.Empty;
            string filePath = string.Empty;
            int iSuccess = 0;
            int iTotal = 0;
            sbResult.Append(System.DateTime.Now.ToString());
            //Set value
            if (string.IsNullOrEmpty(tmpId))
            {
                tmpId = "SALARY";
            }
            SPListItem mailTemp = getItemByTempID(tmpId);
            if (mailTemp == null)
            {
                sbResult.Append("<div style=‘color:red‘>Cannot get the mail template ‘" + tmpId + "‘.</div>");
                return sbResult.ToString();
            }
　　　　　　　//set file address
            folderPath = @"E:\Batter\TFS\S\";
            emailTitle=Convert.ToString(mailTemp["EmailTitle"]);
            emailFrom = Convert.ToString(mailTemp["MailFrom"]);
            emailBody=Convert.ToString(mailTemp["MailBody"]);
            #endregion
            
            try
            {
                using (SPSite site = new SPSite(SPContext.Current.Web.Url))
                {
                    using (SPWeb web = site.OpenWeb())
                    {
                        SPList list = web.Lists["UserList"];
                        SPListItemCollection items = list.Items;
                        iTotal = items.Count;
                        foreach (SPListItem item in items)
                        {
                            string mailTo = Convert.ToString(item["Email"]);
                            string var1 = Convert.ToString(item["Var1"]);
                            string var2 = Convert.ToString(item["Var2"]);
                            string var3 = Convert.ToString(item["Var3"]);
                            string htmlBodyContent = emailBody.Replace("{Var1}", var1).Replace("{Var2}", var2).Replace("{Var3}", var3);
                            filePath = folderPath + "xxx"+var1+".doc";
                            using (var message = new MailMessage())
                            {
                                SPWebApplication webApp = web.Site.WebApplication;
                                message.Subject = emailTitle;
                                message.From = new MailAddress(emailFrom);
                                message.To.Add(mailTo); 
                                AlternateView htmlBody = AlternateView.CreateAlternateViewFromString(htmlBodyContent, null, "text/html");
                                
                                try
                                {
                                    Attachment myAttachment = new Attachment(filePath);
                                    message.Attachments.Add(myAttachment);
                                }
                                catch (Exception ex)
                                {
                                    sbResult.Append("<div style=‘color:Red‘>To: " + mailTo + " Error! " + ex.Message + "</div><br />");
                                    continue;
                                }

                                message.AlternateViews.Add(htmlBody);
                                var smtpClient = new SmtpClient
                                {
                                    Host =
                                        webApp.OutboundMailServiceInstance.Server.Name,
                                    UseDefaultCredentials = true,
                                    DeliveryMethod = SmtpDeliveryMethod.Network
                                };
                                try
                                {
                                    smtpClient.Send(message);
                                    sbResult.Append("<div style=‘color:blue‘>To: " + mailTo  + " Success!</div>");
                                    iSuccess++;
                                }
                                catch (Exception ex)
                                {
                                    sbResult.Append("<div style=‘color:Red‘>To: " + mailTo + " Error! " + ex.Message + "</div><br />");
                                }
                            }
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                sbResult.Append(ex.Message);
            }
            sbResult.Append(string.Format("Success: {0}     Total: {1}<br />",iSuccess,iTotal));
            sbResult.Append(System.DateTime.Now.ToString());
            return sbResult.ToString(); ;

        }
        
        private SPListItem getItemByTempID(string tempId)
        {
            SPListItem item = null;
            SPSecurity.RunWithElevatedPrivileges(delegate()
            {
                using (SPSite site = new SPSite(SPContext.Current.Web.Url))
                {
                    site.AllowUnsafeUpdates = true;
                    using (SPWeb web = site.OpenWeb())
                    {
                        web.AllowUnsafeUpdates = true;
                        SPList list = web.Lists["Template"];
                        if (list != null)
                        {
                            SPQuery query = new SPQuery();
                            query.Query = string.Format("<Where><Eq><FieldRef Name=\"Title\" /><Value Type=\"Text\">{0}</Value></Eq></Where>", tempId);
                            query.RowLimit = 1;

                            SPListItemCollection items = list.GetItems(query);
                            if (items != null)
                            {
                                if (items.Count == 1)
                                {
                                    item = items[0];
                                }
                            }
                        }
                        web.AllowUnsafeUpdates = false;
                    }
                }
            });
            return item;
        }
    
    }

<style type="text/css">
    .sendSalaryMail {
        margin-left: 20px;
    }

    .trainingtitle {
        color: rgb(125, 10, 60);
        font-size: 16px;
        margin-bottom: -10px;
        font-weight: bold;
        margin-bottom: 5px;
    }

    .colTitle {
        font-weight: bold;
        color: Black;
    }
</style>
<div class="sendSalaryMail">
    <div class="trainingtitle">Send E-Mail <b>-- Only xxx can click!! </b></div>
    <br />
    <div class="colTitle">Email Template ID: </div>
    <asp:TextBox ID="tb_TempId" runat="server" Width="340px"></asp:TextBox><div>Defalut is "xxx"</div>
    <br />
    <div class="colTitle">Has File: <asp:CheckBox ID="cb_HasFile" runat="server" Text="Yes" /></div>
    <br />
    <asp:Button ID="bt_SendMail" runat="server" Text="Send xx xx" Height="50px"
        Width="350px" OnClick="bt_SendMail_Click" /><br />
    <div style="margin-top: 10px;">
        <asp:UpdatePanel runat="server" ID="UpdatedPanel1" UpdateMode="Conditional">
            <Triggers>
                <asp:AsyncPostBackTrigger ControlID="bt_SendMail" />
            </Triggers>
            <ContentTemplate>
                <fieldset style="border: none; padding: 0px">
                    <asp:Label ID="lbResult" runat="server" ForeColor="#0000CC" Font-Size="Medium"></asp:Label>
                </fieldset>
            </ContentTemplate>
        </asp:UpdatePanel>
    </div>
</div>