Olaf and I were cracking away on some SharePoint 2010 work which we thought should be simple…point SPMetal to the site and start LINQ-ing to our hearts content…..

with the one exception that we couldn’t select items from a list based on their Content Type.

By default SPMetal.exe doesn’t include these ‘system’ fields (apart from ID + Title – go figure) and the secret is to use an Override file.

The good oil is:http://msdn.microsoft.com/en-us/library/ee535056.aspx
(Here’s a good article on how .NET Types are mapped to SharePoint - http://msdn.microsoft.com/en-us/library/ee536245.aspx)

The simple override/parameters file:

<Web AccessModifier="Internal" xmlns="http://schemas.microsoft.com/SharePoint/2009/spmetal">
  <ContentType Name="Item" Class="Item">
    <Column Name="ContentType" Member="ContentType" />
   
  </ContentType>
  
</Web>

The SPMetal Command Line

The VS.NET Code

 static void Main(string[] args)
        {
            using (BreezeDataContext dc = new BreezeDataContext("http://breezelocal"))
            {
                var myitems = from i in dc.GetList<ContentListTraining>("My Content List")
                              where i.ContentType == "Training"
                              select i;
                var courses = myitems.ToList<ContentListTraining>();
 
                Console.WriteLine("There are {0} items",courses[0].Title);
                    
            }
 
            Console.ReadLine();
        }