Have you ever needed to create a custom field type for Sitecore Web Forms for Marketers (WFFM)? Have you ever then needed to use that field type in the Send Email Message action in the To/From/CC field? By default, that editor only lets you select field of type Email. Here’s how you extend it to allow additional field types.
- Find the /sitecore/system/Modules/Web Forms for Marketers/Settings/Actions/Save Actions/Send Email Message item.
- Add this to the QueryString field:
AllowedToTypes={84ABDA34-F9B1-4D3A-A69B-E28F39697069}|{1D2C0726-D622-4989-B545-4C37A63B97BB}
NOTE: {84ABDA34-F9B1-4D3A-A69B-E28F39697069} is the out of the box Email type, then add your custom types after that separated by a pipe.

Now when you use the Send Email Message save action, your custom type will appear in the To field. To control the other email fields on that dialog, use the following querystring parameters.
- AllowedToTypes
- AllowedFromTypes
- AllowedCCTypes
- AllowedSubjectTypes
For more specific information, reference “Sitecore.Forms.Shell.UI.Dialogs.SendMailEditor, Sitecore.Forms.Core” with Reflector.