/// <summary>
/// Specifies the related objects to include in the query results using
/// a lambda expression listing the path members.
/// </summary>
/// <returns>A new System.Data.Objects.ObjectQuery<T> with the defined query path.</returns>
public static IQueryable <T> Include <T>(this IQueryable <T> query, Expression <Func <T, object> > path)
{
// If it's a System.Data.Objects.ObjectQuery, apply the include, otherwise ignore:
if (query is ObjectQuery <T> )
{
// Retrieve member path:
List <ExtendedPropertyInfo> members = new List <ExtendedPropertyInfo>();
EntityFrameworkHelper.CollectRelationalMembers(path, members);
// Build string path:
StringBuilder sb = new StringBuilder();
string separator = "";
foreach (ExtendedPropertyInfo member in members)
{
if (member.ReferenceOnly)
{
break;
}
sb.Append(separator);
sb.Append(member.PropertyInfo.Name);
separator = ".";
}
// Apply Include:
if (sb.Length > 0)
{
return(((ObjectQuery <T>)query).Include(sb.ToString()));
}
else
{
return(query);
}
}
else
{
// Object is not an EF ObjectQuery:
return(query);
}
}
/// <summary>
/// Attaches multiple entire objectgraphs to the context.
/// </summary>
public static T[] AttachObjectGraphs <T>(this ObjectContext context, IEnumerable <T> entities, params Expression <Func <T, object> >[] paths)
{
T[] unattachedEntities = entities.ToArray();
T[] attachedEntities = new T[unattachedEntities.Length];
Type entityType = typeof(T);
if (unattachedEntities.Length > 0)
{
// Workaround to ensure the assembly containing the entity type is loaded:
// (see: https://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=3405138&SiteID=1)
try { context.MetadataWorkspace.LoadFromAssembly(entityType.Assembly); }
catch { }
#region Automatic preload root entities
// Create a WHERE clause for preload the root entities:
StringBuilder where = new StringBuilder("(1=0)");
List <ObjectParameter> pars = new List <ObjectParameter>();
int pid = 0;
foreach (T entity in unattachedEntities)
{
// If the entity has an entitykey:
EntityKey entityKey = ((IEntityWithKey)entity).EntityKey;
if (entityKey != null)
{
where.Append(" OR ((1=1)");
foreach (EntityKeyMember keymember in entityKey.EntityKeyValues)
{
string pname = String.Format("p{0}", pid++);
where.Append(" AND (it.[");
where.Append(keymember.Key);
where.Append("] = @");
where.Append(pname);
where.Append(")");
pars.Add(new ObjectParameter(pname, keymember.Value));
}
where.Append(")");
}
}
// If WHERE clause not empty, construct and execute query:
if (pars.Count > 0)
{
// Construct query:
ObjectQuery <T> query = (ObjectQuery <T>)context.PublicGetProperty(context.GetEntitySetName(typeof(T)));
foreach (var path in paths)
{
query = (ObjectQuery <T>)query.Include(path);
}
query = query.Where(where.ToString(), pars.ToArray());
// Execute query and load entities:
//Console.WriteLine(query.ToTraceString());
query.Execute(MergeOption.AppendOnly).ToArray();
}
#endregion Automatic preload root entities
// Attach the root entities:
for (int i = 0; i < unattachedEntities.Length; i++)
{
attachedEntities[i] = (T)context.AddOrAttachInstance(unattachedEntities[i], true);
}
// Collect property paths into a tree:
TreeNode <ExtendedPropertyInfo> root = new TreeNode <ExtendedPropertyInfo>(null);
foreach (var path in paths)
{
List <ExtendedPropertyInfo> members = new List <ExtendedPropertyInfo>();
EntityFrameworkHelper.CollectRelationalMembers(path, members);
root.AddPath(members);
}
// Navigate over all properties:
for (int i = 0; i < unattachedEntities.Length; i++)
{
NavigatePropertySet(context, root, unattachedEntities[i], attachedEntities[i]);
}
}
// Return the attached root entities:
return(attachedEntities);
}
