The first thing I did, was install the Web Part Templates for Visual Studio .NET on my machine. To do this, it required the Microsoft.SharePoint.dll during installation. So I decided to install Windows SharePoint Services first, which was freely available on the Microsoft Download website.
After I installed SharePoint, I discovered the SmartPart. This is a special WebPart, created by Jan Tielens and Fons Sonnemans, which allows you to encapsulate a regular ASP.NET User Control in a WebPart. This is a great solution because it gives you the productivity of using the designer and the power of accessing the SharePoint Object Model at the same time.
As this WebPart would be storing data, I had to start looking where to store it. My first idea was to store it right in the SharePoint database, but there was almost no information on it and I got advised it wasn’t a good thing to put third party data in the database. In the end I created two Custom Lists in SharePoint, who would act as database tables to store the data.
The next step was the creation of the User Control. To do this, references to Microsoft.SharePoint.dll and SmartPart.dll had to be added, the SmartPart, Microsoft.SharePoint and Microsoft.SharePoint.WebControls namespaces had to be imported and the IUserControl interface had to be implemented. This interface takes care of the link between your User Control and the SharePoint Web.
After this, it was possible to access everything of the SharePoint Object Model. For example, to fill a dropdown list with the available users, I used the following code:
This dropdown was later used as a filter in the administrative part of the WebPart.
To retrieve the available types from the Custom List, I used the following piece:
With code like these small pieces, demonstrating the SharePoint Object Model, I created a small User Control, containing a DataGrid to display the items, some input fields to add new items and a dropdown list with users, to filter on when being logged on as an Administrator.