Guest Author:Brett Lonsdale

SharePoint 2010 has introduced a new type of List called the External List.  The External List is used for displaying content that comes from Business Connectivity Services (BCS) Enterprise content types.  Business Connectivity Services is the replacement in SharePoint 2010 for The Business Data Catalog (BDC) in SharePoint 2007. 

The BDC provided a read only view of your line of business data allowing you to display the data in Web Parts, Search Line of Business data, and use it within lists and libraries via the Business Data Column.  It was possible to right back to the data source using BDC via your own custom web parts or by using BDC Meta Man.

Business Connectivity Services allows you to work with your Line of Business Data within SharePoint as though it was a SharePoint List.  External Lists provide you with full CRUD functionality meaning you can Create, Read, Update and Delete data all the way back to the data source.  If you are familiar with using SharePoint Lists, you will be at home with an External List.

As well as providing you with the CRUD functionality on your Line of Business Data, you also receive all of the other List advantages such as:  Ability to create Views, additional Columns, Filters, and Security.  The External List can also be added to a web part page as a List View Web Part which now offers Ajax functionality meaning better performance from your web part pages and fewer page refreshes.

As you have probably read from previous BCS articles on our site, the External Content Type is created using either SharePoint Designer 2010 or Visual Studio 2010.  Once the External Content Type is created, you can create the external list either from the Create page in SharePoint or via SharePoint Designer. Below is a screenshot of an External List (Default View).

Every View is manipulated as though it was a SharePoint View, and therefore you can create additional views selecting which columns you would like to display, Categorization, and Sorting options.  The only view type that is unavailable is the Datasheet view.

From each view within the External List, you will find options on the ribbon to make the data available offline which is another new feature of BCS.  Options include connecting to Outlook which is useful for Contacts or Tasks from your Line of Business System (Updates also work from Outlook), or you can use SharePoint Workspace.  SharePoint Workspace is a tool that allows you to work with the List offline and then synchronize it at a later date when you are online.

To Insert, and Update items, a form is used which is selected from the External List ribbon.  The below form is an example of the out-of-the-box New Item form which was created at the time of creating my External List. SharePoint does a good job of recognizing some of the validation options such as Data Type and Required fields.  However, for more complex validation, and for the creation of lookups etc, you may decide to create a InfoPath form from within SharePoint Designer as a replacement.  

To modify one of the forms using InfoPath 2010, you will need to open up your site using SharePoint Designer 2010.  Navigate to Lists and Libraries using the Navigation section, and then click on the external list.  You will see the forms available to edit from within SharePoint Designer.  However, you will have little control over them there! To edit them in InfoPath 2010, click the button on the ribbon to ‘Design Forms in InfoPath 2010’ as shown below.

Your Form will then be shown with all of the available fields on the right hand side in the Fields section.  You now have full control including the ability to format, re-order, rename, add validation rules, add formatting, default values, control types etc.  The only thing that I found frustrating was I don’t have the ability to do an external data lookup.  E.g. lookup a list of Suppliers.

In my example, I am going to add a validation rule.  Each time my stock level is below 5, it will become clearer as the text will be formatted in Red and Bold.

Once you have made all of your required changes, you can submit the form back to the External List by choosing File, Publish, External List.  That is it! Below you can see the form in use within SharePoint with the stock level of 3 highlighted in red.

Guest Author:Brett Lonsdale

Brett Lonsdale is a SharePoint developer who specializes within the Business Data Catalog, co-owner of Lightning Tools Ltd, Co-host on The SharePoint Pod Show www.sharepointpodshow.com..  Strategically (kind of) Brett has based himself in Florida where he lives with his wife and daughter.  You can read Brett’s blog on www.brettlonsdale.com, and also follow him on twitter @brettlonsdale