接上
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/// <summary>
/// 最多收件人数量
/// </summary>
public int RecipientMaxNum
{
    set
    {
        recipientmaxnum = value;
    }
}

/// <summary>
/// 邮件服务器域名和验证信息
/// 形如："user:pass@www.server.com:25"，也可省略次要信息。如"user:pass@www.server.com"或"www.server.com"
/// </summary>    
public string MailDomain
{
    set
    {
        string maidomain=value.Trim();
        int tempint;

        if(maidomain!="")
        {
            tempint=maidomain.IndexOf("@");
            if(tempint!=-1)
            {
            string str=maidomain.Substring(0,tempint);
                        MailServerUserName=str.Substring(0,str.IndexOf(":"));
                        MailServerPassword=str.Substring(str.IndexOf(":")+1,str.Length-str.IndexOf(":")-1);
                        maidomain=maidomain.Substring(tempint+1,maidomain.Length-tempint-1);
            }
                tempint=maidomain.IndexOf(":");
            if(tempint!=-1)
            {
                mailserver=maidomain.Substring(0,tempint);
                        mailserverport=System.Convert.ToInt32(maidomain.Substring(tempint+1,maidomain.Length-tempint-1));
                    }
                    else
                    {
                        mailserver=maidomain;

                    }

                
                }