Metadata API - ASP.NET Dynamic Data - page 194

If you need to access the list of all tables, you can use the Tables property. It is a read-only
collection of MetaTable instances, which you can iterate through using a foreach loop or
interrogate using LINQ to Objects. If you are interested only in tables that will be visible
to the current user, you can use the VisibleTables property.
NOTE
The VisibleTables property of the MetaModel class returns a read-only list of tables,
despite its type, List<MetaTable> , which implies the ability to change it. Any changes
you make to the VisibleTables list are ignored, and you should treat it as a read-only
collection.
Keep in mind that iterating through the list of tables at runtime can be costly, so if you
need a particular table, use one of the methods the MetaModel class provides for that
purpose instead:
public MetaTable GetTable(string uniqueTableName);
public MetaTable GetTable(Type entityType);
The GetTable method that takes a string that contains a table name is the most efficient
way to retrieve a specific table from the MetaModel . This method retrieves the MetaTable
from the dictionary of table names and objects that MetaModel maintains internally. You
typically use one of these methods when building custom pages that don't rely on
dynamic data URL routing:
MetaTable table = Global.DefaultModel.GetTable(“Products”);
MetaTable table = Global.DefaultModel.GetTable(typeof(Product));
Although using the GetTable overload that takes an entity Type is more elegant (because it
allows you to avoid using hard-coded literals or string constants to specify the table
name), it is actually less efficient as it iterates through the entire list of tables to find the
one with a matching type. Although the performance impact of a single table lookup
might not be noticeable, keep in mind that it quickly increases as your data model
becomes more complex and as the number of users accessing your application increases.
NOTE
The GetTable(string) method is also used by the DynamicDataRouteHandler when
routing dynamic URLs to page templates. It extracts the table name from the URL, calls
the GetTable method of the MetaModel , and stores the MetaTable object it returns in
the Items dictionary of the HttpContext . If you simply need the MetaTable object for the
current request, the fastest way to access it is by calling the static GetRequestMetaTable
method of the DynamicDatarouteHandler class, as shown here:
MetaTable table = DynamicDataRouteHandler.GetRequestMetaTable(Page.Context);