Question

I upgraded an old project started in ef4 but now I migrated it to ef5.

This is the old code:

protected void SaveEntity<T>(T entity)
{
        using (DocsManagerContainer context = new DocsManagerContainer())  
                {  
                    string entityType = typeof(T).ToString();  
                    GetLogger().LogMessage("Save " + entityType + " started", LogLevel.Info);  
                    DbTransaction transaction = null;  
                    try  
                    {  
                        context.Connection.Open();  
                        transaction = context.Connection.BeginTransaction();  
                        context.AddObject(typeof(T).Name + "s", entity);  
                        transaction.Commit();  
                        context.SaveChanges();  
                    }  
                    catch (Exception e)  
                    {  
                        GetLogger().LogMessage("Save " + entityType + " thrown error :", e, LogLevel.Error);  
                        throw e;  
                    }  
                    finally  
                    {  
                        context.Connection.Close();  
                        transaction = null;  
                    }  
                    GetLogger().LogMessage("Save " + entityType + " ended", LogLevel.Info);  
                }  
    }

I’ve upgraded almost all of the code except : context.AddObject(typeof(T).Name + "s", entity);, but this isn’t supported anymore.
How can I upgrade this ?

p.s. I do want to use generic code, not to use switches to add the corresponding object to correct ObjectSet
p.s. Error if I use .Set().Add(entity) is :

Error   2   The type 'T' must be a reference type in order to use it as parameter 'TEntity' in the generic type or method 'System.Data.Entity.DbContext.Set<TEntity>()' D:\work\DocsManager\trunk\DocsManagerDataMapper\EF4Factory\BaseEF4Factory.cs    64  21  DocsManagerDataMapper

Answer 1

With DbContext you can use context.Set<T>().Add(entity);

Example: context.Set<User>() is equivalent to context.Users so context.Set<User>().Add(myUser) is equivalent to context.Users.Add(myUser).

You want something closer to this:

protected void SaveEntity<T>(T entity)
    where T : class
{
    using (DocsManagerContainer context = new DocsManagerContainer())  
    {  
        DbTransaction transaction = null;  
        try  
        {  
            context.Connection.Open();  
            transaction = context.Connection.BeginTransaction();  
            context.Set<T>().Add(entity);  
            transaction.Commit();  
            context.SaveChanges();  
        }  
        finally  
        {  
            context.Connection.Close();  
                transaction = null;  
        }
    }
}