App.config中的多个mailSettings

Question

I currently have an App.config like so:

<system.net>
    <mailSettings>
      <smtp from="xxx@xxnn.co.uk">
        <network host="nn.nn.nn.nn"
                 port="25"
                 userName="myname"
                 password="mypass"/>
      </smtp>
    </mailSettings>
  </system.net>

And send MailMessage msg using:

SmtpClient client = new SmtpClient();
try { client.Send(msg);

But how do I configure 3 or 4 different <mailSettings> and pull in the correct configuration at run time?

The mailbox to send FROM will vary depending on row["Ledger"] below

foreach (DataRow row in accounts.Tables[0].Rows)
{
    string cust = row["Account"].ToString();
    string site = row["Ledger"].ToString();
    string mail = row["Email"].ToString();`

Answer 1

Well after a bit more research i came up with the following solution: in App.Config

    <configSections>
    <sectionGroup name="Ledgers">
      <section name="1stCompany" type="System.Configuration.NameValueSectionHandler" />
      <section name="2ndCompany" type="System.Configuration.NameValueSectionHandler" />
      <section name="3rdCompany" type="System.Configuration.NameValueSectionHandler" />
      <section name="4thCompany" type="System.Configuration.NameValueSectionHandler" />
    </sectionGroup>
  </configSections>
  <Ledgers>
    <1stCompany>
      <add key="host" value="nn.nn.nn.nn"/>
      <add key="user" value="xxx1@xxx1.co.uk"/>
      <add key="pass" value="password"/>
      <add key="from" value="xxx1@xxx1.co.uk"/>
    </1stCompany>
    <2ndCompany>
      <add key="host" value="nn.nn.nn.nn"/>
      <add key="user" value="xxx2@xxx2.co.uk"/>
      <add key="pass" value="password"/>
      <add key="from" value="xxx2@xxx2.co.uk"/>
    </2ndCompany>
    <3rdCompany>
      <add key="host" value="nn.nn.nn.nn"/>
      <add key="user" value="xxx3@xxx3.co.uk"/>
................................. etc ...........
................................. etc .................
</Ledgers>
</configuration>

Then I wrote this method which loops through configSections to match the company names and pull in the mailserver settings

private SmtpClient findClient(string site, ref string from)
    {
        // Get the application configuration file.
        Configuration config =
            ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);

        // Get the collection of the section groups.
        ConfigurationSectionGroupCollection myCollect = config.SectionGroups;

        string host = "";
        string user = "";
        string pass = "";

        SmtpClient client = new SmtpClient();

        foreach (ConfigurationSectionGroup myGroups in myCollect)
        {
            if (myGroups.Name != "Ledgers") continue;

            foreach (ConfigurationSection mySection in myGroups.Sections)
            {
                string ledger = mySection.SectionInformation.Name.ToString();
                Console.WriteLine("Site is " + site + "ledger is " + ledger);
                if (ledger.Equals(site, StringComparison.Ordinal))
                {
                    var section = ConfigurationManager.GetSection(
                        mySection.SectionInformation.SectionName)
                            as NameValueCollection;

                    host = section["host"];
                    user = section["user"];
                    pass = section["pass"];
                    from = section["from"];

                    Console.WriteLine("\n\nHost " + host + "\nUsername " +
                                user + "\nPassword " + pass + "\nFrom " + from);

                    client.Port = 25;
                    client.Host = host;
                    client.Credentials = new System.Net.NetworkCredential(user, pass);

                    break;
                }
            }
        }
        return client;
    }

The class method seems rather laborious. I am sure I could go straight to the required section because I know which section I need because it's heading matches the parameter 'site'. But it is working so is fine for now

Answer 2

You can specify the from address in the message object:

msg.From = new MailAddress("fred@somewhere.com");

So now all you need to worry about is mapping the site value to a from email address. For example if you keep them in the appSettings of your app.config :

<appSettings>
    <add key="Site1" value="someone@somewhere.com" />
    <add key="Site2" value="someone@somewhere-else.com" />
</appSettings>

You can get it like this:

public string GetFromAddressBySite(string site)
{
    return ConfigurationManager.AppSettings[site];
}

As an example, your full code might look like this

SmtpClient client = new SmtpClient();

foreach (DataRow row in accounts.Tables[0].Rows)
{
    string cust = row["Account"].ToString();
    string site = row["Ledger"].ToString();
    string mail = row["Email"].ToString();

    //Get your email address, say, from the app.config file
    string fromAddress = GetFromAddressBySite(site);

    MailMessage msg = new MailMessage
    {
        From = new MailAddress(fromAddress),
        Subject = "Hello!",
        Body = "..."
    };

    msg.To.Add(new MailAddress(mail));

    client.Send(msg);
}

Note : You can also store server host, port etc. in a settings file and use them too:

var client = new SmtpClient("your.mailserver.com", 25);

Answer 3

You don't have to pick up your settings from mailSettings . You could use your own configuration system, such as a JSON file:

{
    "PublicEmailAddress" : { "From" : "external@mycompany.com" },
    "InternalEmailAddress": { "From" : "internal@mycompany.com"}
}

You'd write code on startup to read in the configuration and store the configuration in memory, then select the appropriate one based on row["Ledger"] .