How can I pass some information in to a Sitecore Webforms for Marketers custom message processor pipeline?

I have a site built using Sitecore 7.5 and Webforms for Marketers 2.5. I am trying to create a custom email message processor pipeline command that will change the TO field for the email before it goes out. But the proper email address needs to come from a Session variable.

Here is my class:

public class CustomEmailMessageProcessor
{
    public void Process(ProcessMessageArgs args)
    {
        //Change the TO address for the email based on the selection in the Subject field
        var subjectField = args.Fields.GetEntryByName("Subject");
        if (subjectField == null)
        {
            return;
        }

        //The value of the selected item will be the ID of a Subject Option
        var selectedSubjectOptionItem = Sitecore.Context.Database.GetItem(new ID(subjectField.Value));
        if (selectedSubjectOptionItem == null)
        {
            return;
        }

        var selectedSubjectOption = selectedSubjectOptionItem.GlassCast<Contact_Us_Subject_Option>();

    //Based on the currently selected Region in the Session variable, get the proper
    //child of selectedSubjectOption to populate the TO field
        ???

        if (args.To.Length != 0)
        {
            args.To.Append(",");
        }
        args.To.Append(proper email address goes here);
    }
}

And here is my associated config:

  <processMessage>
    <processor type="Sitecore.Form.Core.Pipelines.ProcessMessage.ProcessMessage, Sitecore.Forms.Core" method="ExpandLinks" />
    <processor type="Sitecore.Form.Core.Pipelines.ProcessMessage.ProcessMessage, Sitecore.Forms.Core" method="ExpandTokens" />
    <processor type="Sitecore.Form.Core.Pipelines.ProcessMessage.ProcessMessage, Sitecore.Forms.Core" method="AddHostToItemLink" />
    <processor type="Sitecore.Form.Core.Pipelines.ProcessMessage.ProcessMessage, Sitecore.Forms.Core" method="AddHostToMediaItem" />
    <processor type="Sitecore.Form.Core.Pipelines.ProcessMessage.ProcessMessage, Sitecore.Forms.Core" method="AddAttachments" />
    <processor type="Sitecore.Form.Core.Pipelines.ProcessMessage.ProcessMessage, Sitecore.Forms.Core" method="BuildToFromRecipient" />
    <!-- Custom setting -->
    <processor type="myProject.CustomEmailMessageProcessor, myProject" method="Process" />
    <processor type="Sitecore.Form.Core.Pipelines.ProcessMessage.ProcessMessage, Sitecore.Forms.Core" method="SendEmail" />
  </processMessage>

The user will select a Subject from a dropdown list on the form. The value of each Subject will be the Guid of a corresponding item. That subject item will have children. Each child will have an email address and will correspond to a Region item in the system. I will then find the child item that matches the Region ID that is stored in Session. Then I will have the correct email address to send the email to.

However I have no idea how to access the Session variable from within the pipeline (or if it is even possible). It doesn't have to be Session. I am happy to pass in the currently selected Region in some other fashion. I just need some way to pass information in that can be accessed from the pipeline code.

Thanks, Corey

When using the Sitecore WFFM webservice, the save action is run on the CMS, shell site. The save action don't know anything about the user session. A different more standard solution is create a (custom) Field hidden, and set there the value you can use to find the needed email address. Create a custom save action and do there your e-mail sending.

Note: If you do not have a good identifier to find the email address watch out with putting an email address or to simple identifier in a (hidden) form value, it can be abused.

Example of a hidden field, based on a <input type="text" .....> for Webforms

using System;
using System.Web.UI;
using System.Web.UI.WebControls;
using Sitecore.Form.Web.UI.Controls;

namespace StockpickSitecore.Controls.WFFM.CustomFields
{
    public class HiddenEmailfield : SingleLineText
    {
        private static readonly string baseCssClassName = "scfSingleLineTextBorder";
        private string CssClassName { get; set; }

        public int MaxLength
        {
          get
          {
            return this.textbox.MaxLength;
          }
          set
          {
            this.textbox.MaxLength = value;
          }
        }

        public int MinLength { get; set; }

        public new string CssClass
        {
          get
          {
            return base.CssClass;
          }
          set
          {
            base.CssClass = value;
          }
        }

        public HiddenEmailfield()
        {
            this.Text = "info@yourdomein.com";
        }

        protected override void OnInit(EventArgs e)
        {
            this.Attributes.Add("style", "display: none;");
          this.textbox.CssClass = "scfSingleLineTextBox";
          this.help.CssClass = "scfSingleLineTextUsefulInfo";
          this.generalPanel.CssClass = "scfSingleLineGeneralPanel";
          this.title.CssClass = "scfSingleLineTextLabel";
          this.textbox.TextMode = TextBoxMode.SingleLine;
          this.Controls.AddAt(0, (Control) this.generalPanel);
          this.Controls.AddAt(0, (Control) this.title);
          this.generalPanel.Controls.AddAt(0, (Control) this.help);
          this.generalPanel.Controls.AddAt(0, (Control) this.textbox);
        }
    }
}

Change the constructor HiddenEmailfield and set the this.Text with the Session value.

Creat a item in Sitecore below /sitecore/system/Modules/Web Forms for Marketers/Settings/Field Types/Custom/ based on Template: /sitecore/templates/Web Forms for Marketers/Field Type

Fill in the Assembly : StockpickSitecore for Example

Fill in the Class: StockpickSitecore.Controls.WFFM.CustomFields.HiddenEmailfield

Now you can use HiddenEmailfield in you webform als field type