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Modify SharePoint host web lists at creation time

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When you create a new list in the host web, you can use a ListAdded remote event receiver to modify that list. For example, you can enable versioning, or add a content type to the list, or make any other changes implemented by the client object model (CSOM).

When the list is added to the host web, you need to programmatically attach the event receiver. The Core.EventReceiversBasedModifications sample shows you how to use a provider-hosted add-in to do this. When the add-in is installed, an AppInstalled event occurs, and you use this event to attach the ListAdded event.

Before you begin

To get started, download the Core.EventReceiversBasedModifications sample add-in from the Office 365 Developer Patterns and Practices project on GitHub.

Note

The code in this article is provided as-is, without warranty of any kind, either express or implied, including any implied warranties of fitness for a particular purpose, merchantability, or non-infringement.

Attach the ListAdded event

To implement the event handlers for the add-in, display the properties for the SharePoint project, and set both Handle Add-in Installed and Handle Add-in Uninstalling to True.

The following code example shows how the AppInstalled event receiver is modified to attach the ListAdded event receiver.

bool rerExists = false;
cc.Load(cc.Web.EventReceivers);
cc.ExecuteQuery();

foreach (var rer in cc.Web.EventReceivers)
{
  if (rer.ReceiverName == RECEIVER_NAME)
  {
    rerExists = true;
  }
}

if (!rerExists)
{
  EventReceiverDefinitionCreationInformation receiver = new EventReceiverDefinitionCreationInformation();
  receiver.EventType = EventReceiverType.ListAdded;

  // Get WCF URL where this message was handled.
  OperationContext op = OperationContext.Current;
  Message msg = op.RequestContext.RequestMessage;
  receiver.ReceiverUrl = msg.Headers.To.ToString();
  receiver.ReceiverName = RECEIVER_NAME;
  receiver.Synchronization = EventReceiverSynchronization.Synchronous;
  cc.Web.EventReceivers.Add(receiver);
  cc.ExecuteQuery();
}

Customize the added lists

When the ListAdded event handler is firing, the following code runs.

private void HandleListAdded(SPRemoteEventProperties properties)
{
  using (ClientContext cc = TokenHelper.CreateRemoteEventReceiverClientContext(properties))
  {
    if (cc != null)
    {
      try
        {
          if (properties.ListEventProperties.TemplateId == (int)ListTemplateType.DocumentLibrary)
          {
          //set versioning 
   cc.Web.GetListByTitle(properties.ListEventProperties.ListTitle).UpdateListVersioning(true, true);
          }
        }
         catch (Exception ex)
         {
           System.Diagnostics.Trace.WriteLine(ex.Message);
         }
       }
    }
  }
}

Uninstall the event receiver

When the add-in is uninstalled, the event receiver should also be removed. To make this work during debugging, go to the Add-ins in testing library and use the remove option on the add-in. This triggers the AppUninstalling event with the proper permissions to remove the created remote event handler.

If you just close the browser or uninstall the add-in from site contents, either the event receiver never fires or the AppUninstalling event receiver runs with insufficient permissions to remove the ListAdded event receiver. This is because add-ins are deployed differently when they are side-loaded, which is what Visual Studio does when you press F5.

Note

We recommend that you test this sample in a clean developer site.

See also