Custom Actions for list items assigned programmatically

Custom actions are usually deployed in a declarative manner, such as an Elements.xml file. They can be deployed to a specific content type in case your document library inherits from the specific content type, such as below:

<?xml version="1.0" encoding="utf-8"?>

<Elements xmlns="http://schemas.microsoft.com/sharepoint/">

  </CustomAction>

  <CustomAction

  Id="{ACE9ADB4-A9CE-4503-9819-AC9C6FC09E01}"

  RegistrationType="ContentType"

  RegistrationId="0x01010059dee241fa9e47e8aded6c595cb2b406"

  Location="EditControlBlock"

  Sequence="101"

  Title="Approve/Reject Monthly Report">

    <UrlAction Url="javascript:MyNamespace.retrieveListItems({ItemId});"/>

  </CustomAction>

  

</Elements>

       

However, when your document library gets deployed via code, such as  feature receiver, and especially if the document library is not associated with a content type, there is the option to attach a custom action programmatically such as  in the example below.           

                    Guid formlibID = web.Lists.Add("My Library", string.Empty, SPListTemplateType.XMLForm);

                    SPList formLib = web.Lists[formlibID];

                    SPUserCustomAction printForm = formLib.UserCustomActions.Add();

                    printForm.Title = "Print Form";

                    printForm.Url = "javascript:MyNamespace.printForm({ItemId},'{ItemUrl}')";

                    printForm.Location = "EditControlBlock";

                    printForm.Update();

In both examples, the custom action performs some javascript logic (in this case the two functions both open up a modal popup), that takes in the current items' out-of-the-box ID and URL.