Alf Nilsson talks

While adding some Blocks to a project I was thinking of a concept that I’ve had in mind for a while. Some way to make it easier to hook your logic to EPiServer events such as creating pages, publishing pages.

The project can be downloaded from my repository on GitHub. I hope this will make your event handling in EPiServer much easier!

My example is a block that represents a header to group blocks.

[ContentType(DisplayName = "Column Heading", Description = "A heading in the column", GUID = "0A9BEC10-5795-43D5-B305-130ED6222D8A")]
public class ColumnHeadingBlock : BlockData
{
  [Display(GroupName = SystemTabNames.Content, Order = 1)]
  public virtual string Heading { get; set; }
}

Since it only has one property, it would be nice that it would be populated with the name given when the Block was created.

First approach: override SetDefaultValues

I noticed that the instance of my ColumnHeadingBlock is a ColumnHeadingBlockProxy that seems to be created  by EPiServer.Construction.SharedBlockFactory.CreateSharedBlock and that the proxy also is implementing the IContent Interface. Hence I can Cast my to IContent and retrieve the IContent.Name implementation.

Sadly SetDefaultValues are run before the Name is set and returns null.

Second approach: EPiServer.DataFactory.CreatingContent Event

This seems to do the trick. CreatingContent is triggered after SetDefaultValues and contentEventArgs.Content.Name returns the name I gave when creating the Block.

Wrapping things up: Initialization and reusability

The idea that have been growing inside my head is that I shouldn’t need to clutter global.asax or create InitializationModules everytime I want something to happen when I create, save, publish, move a page.

Therefore I created my EventHelper where I only need to implement an Interface to my Page Type Class where I add the logic to be run under certain Events. This could be re-registering Routes, notifying people, logging things etc when something is done in EPiServer.

In my example where I want to set a value to a Block Property when it is created, the implementation would look like this:

[ContentType(DisplayName = "Column Heading", Description = "A heading in the column", GUID = "0A9BEC10-5795-43D5-B305-130ED6222D8A")]
public class ColumnHeadingBlock : BlockData, ICreatingContent
{
  [Display(GroupName = SystemTabNames.Content, Order = 1)]
  public virtual string Heading { get; set; }

  public void CreatingContent(object sender, ContentEventArgs contentEventArgs)
  {
    Heading = contentEventArgs.Content.Name;
  }
}

Behind the scenes

The project contains an InitializationModule where I hookup basically all Events I could find in the DataFactory. I excluded the LoadingChildren Events since I don’t really know what the best implementation of this could be. Maybe something for a later version?

The CreatingContent Event is hooked up to the method DataFactoryEvents.CreatingContent.

DataFactory.Instance.CreatingContent += DataFactoryEvents.CreatingContent;

The DataFactoryEvents.CreatingContent method looks like this:

public static void CreatingContent(object sender, ContentEventArgs e)
{
  var content = e.Content as ICreatingContent;
  if (content == null)
    return;
  content.CreatingContent(sender, e);
}

Here is a list of the other Events I’m using – as you can see I’ve also implemented Page Events as well as the Content Events.

I have not yet given myself time to see if it’s necessary to be able to implement both Content and Page, but since the Page Event is not obsolete I guess both would be good.

• CheckedInContent
• CheckedInPage
• CheckingInContent
• CheckingInPage
• CreatedContent
• CreatedPage
• CreatingContent
• CreatingPage
• DeletedContent
• DeletedContentLanguage
• DeletedContentVersion
• DeletedPage
• DeletedPageLanguage
• DeletingContent
• DeletingContentLanguage
• DeletingContentVersion
• DeletingPage
• DeletingPageLanguage
• FailedLoadingContent
• FailedLoadingPage
• FinishedLoadingPage
• LoadedContent
• LoadedDefaultContent
• LoadedDefaultPageData
• LoadedPage
• LoadingContent
• LoadingDefaultContent
• LoadingDefaultPageData
• LoadingPage
• MovedContent
• MovedPage
• MovingContent
• MovingPage
• PublishedContent
• PublishedPage
• PublishingContent
• PublishingPage
• SavedContent
• SavedPage
• SavingContent
• SavingPage