I want to create a custom action in SharePoint Designer 2010. This custom action need to appear under 'Action' command of workflow with name "send and email with http attachment". When it starts its fucntionality need to be same as "send an email". Can anyone guide me to create custom action code for the above mentioned logic?
SharePoint Designer provides a collection of workflow actions that are available through the Workflow Designer user interface (UI). Although the range of workflow actions that are included in SharePoint Designer is extensive, it is nevertheless finite. In some cases, you may need to model a business process whose requirements are not met by the existing library of workflow actions that are available in SharePoint Designer.
You can have a look at the below links,
Useful Sharepoint Designer Custom Workflow Activities. --> In this you can make use of the "Send Email with HTTP File attachment activity" --> This activity allows sending emails with attachments retrieved using a web request . Executing Reporting Services report and sending it as an attachment from within SPD workflow would be one such example. Request url is fully customizable and can include workflow variables. Both http and https requests are supported. .