Creating BCS Model

Steps i am following to create my first BDC model in VS2010

1. Open VS and create an empty sharepoint project.
2. Create a folder "BDC", right click on it to add new item.
3. Select Bussiness data connectivity model and name it, "BDCModel" in my case.
Followed step mentioned in following posts.

http://sharepoint.microsoft.com/blog/Pages/BlogPost.aspx?PageType=4&ListId={72C1C85B-1D2D-4A4A-90DE-CA74A7808184}&pID=444
http://sharepoint.microsoft.com/blog/Pages/BlogPost.aspx?PageType=4&ListId={72C1C85B-1D2D-4A4A-90DE-CA74A7808184}&pID=433

One thing to me noted is Type of Return parameterz Type descriptor should be like this.
Name-of-project.ClassName,ModelName

- Set ReadOnly Property to Nothing for Create and Update Methods

- Add Settings.setting file
- Add ConnectionString in file

Add Following code in Service Class
-- ReadItem
 public static TestClass ReadItem(int testID)
        {
            using (BCSLearningDataContext context = new BCSLearningDataContext(Settings.Default.ConnectionString))
            {
                 TestClass  testClass= context. TestClass  .Where(e => e.TestID ==  testID ).FirstOrDefault();
                return  testClass ;
            }
        }
-- ReadList
        public static IEnumerable< TestClass  > ReadList()
        {
            using (BCSLearningDataContext context = new BCSLearningDataContext(Settings.Default.ConnectionString))
            {
                List< TestClass  > dbTestClass= new List< TestClass  >();
                 dbTestClass = context. TestClass  .ToList< TestClass  >();
                return  dbTestClass ;
            }
        }
-- Create
public static  TestClass   Create( TestClass   newTestClass)
        {
            using (BCSLearningDataContext context = new BCSLearningDataContext(Settings.Default.ConnectionString))
            {
                context. TestClass.InsertOnSubmit( newTestClass );
                try
                {
                    context.SubmitChanges();
                    return  newTestClass ;
                }
                catch (System.Data.Linq.ChangeConflictException ex)
                {
                    string error = ex.Message;
                    throw ex;
                }
         
            }
        }
-- Delete
       public static void Delete(int testID)
        {
            using (BCSLearningDataContext context = new BCSLearningDataContext(Settings.Default.ConnectionString))
            {
                 TestClass testClass= context.TestClass .Where(e => e.TestID ==  testID ).FirstOrDefault();
                context. TestClass  .DeleteOnSubmit( testClass );
                try
                {
                    context.SubmitChanges();
                }
                catch (System.Data.Linq.ChangeConflictException ex)
                {
                    string error = ex.Message;
                    throw ex;
                }
           
            }


        }
--Update

 public static void Update(TestClass testClass)
        {
            using (BCSLearningDataContext context = new BCSLearningDataContext(Settings.Default.ConnectionString))
            {
                 TestClass  dbTestClass= context. TestClass.First(thisTest => thisTest.TestID.Equals( testClass.TestID ));
                 dbTestClass.Col1=  testClass.Col1 ;
                 dbTestClass.Col2=  dbTestClass.Col2;
                ...
                try
                {
                    context.SubmitChanges();
                }
                catch (System.Data.Linq.ChangeConflictException ex)
                {
                    string error = ex.Message;
                    throw ex;
                }
                catch (Exception e)
                {
                    throw e;
                }
            }
        }


-- Creating a project to add custom web parts and display data of external list i have created yet.

Step 1. Added Empty sharepoint project.
Step 2. Added Feature.
Step 3.Added following MApped folders.
 - Images
 - Layouts
 - CONTROLTEMPLATES

Step 4. Added new Folder WebParts.
Step 5 Added Visual web part
Added reference to BDCModel project.

Added Access list have columns of external list to bind data to gridview.
BCSLists > Lists > GenericList

-- A class having common functions used by all lists classed and generic functions

public abstract GenericList
{
        protected string listName;
        protected SPList list = null;
        protected bool fromRootWeb = false;

 public GenericList(string listName)
        {
            this.listName = listName;
        }
        public GenericList(string listName, bool fromRootweb)
        {
            this.listName = listName;
            this.fromRootWeb = fromRootweb;
        }


        public string ListName
        {
            get { return listName; }
        }


        public SPList List
        {
            get
            {
                if (list == null)
                {
                    try
                    {
                        list = fromRootWeb ? SPContext.Current.Site.RootWeb.Lists[this.ListName] : SPContext.Current.Web.Lists[this.ListName];
                    }
                    catch (Exception e)
                    {
                        throw new Exception("Unable to access list:" + this.listName);
                    }
                }
                return list;
            }
          }
}

 > BCSLists > Lists > ListTestClass.cs
--1. Added reference to Microsoft.Sharepoint

-- Added a chil class "Columns" , having
-- Added all List Columns in this class.
(e.g) public const string BDCIdentity = "BDC Identity";

-- Added another class "TableColumns" Mapping DB table columns.
(e.g) public const string BDCIdentity = "BdcIdentity";

-- Added a constant mapped to List exact name
(e.g) public const string ListNameTestList = "TestList";

--

Creating a SharePoint 2010 Project



http://www.jones.bz/index.php/2010/05/15/developing-a-bdc-model-on-visual-studio-2010-for-sharepoint-foundation-2010-the-bdc-model-and-external-references/
http://www.jones.bz/index.php/2010/05/08/developing-a-bdc-model-on-visual-studio-2010-for-sharepoint-foundation-2010-install-create-and-deploy/

http://sharepoint.microsoft.com/blog/Pages/BlogPost.aspx?PageType=4&ListId={72C1C85B-1D2D-4A4A-90DE-CA74A7808184}&pID=433

http://fabiangwilliams.wordpress.com/2009/12/03/creating-a-sharepoint-2010-external-content-type-with-crud-methods-using-linq-and-a-sql-lob-system/