LINQ to SQL: using string filename to create a DataContext at runtime

Question

Hi,

With FileInfo I can find the file name of a DataContext .dbml file.

Provided I declare:

Dim DataModel = New AttributeMappingSource().GetModel(GetType(NorthwindDataContext))

With System.Data.LINQ.Mapping I can find the name of all Tables and furthermore their Columns and relationships.

All this thanks to the excellent post from Jomo Fisher here: LINQ to SQL Trick: Get all Table [and Column] Names: http://blogs.msdn.com/jomo_fisher/archive/2007/07/30/linq-to-sql-trick-get-all-table-names.aspx

But how can I achieve same result without explicitly knowing the DataContext Object? I mean how can i "replace" this:

            GetType(NorthwindDataContext))

With:

            dim myDCFile as String = "Northwind.dbml"
            Dim DataModel = .../... GetType(myDCFile))

Answer 1

You could try something like this:

Assembly dataAssembly = Assembly.Load("Your.Data.Assembly");

Type dataContextType = dataAssembly.GetTypes()
           .FirstOrDefault(x => x.IsSubclassOf(typeof(DataContext)));

You would basically load your data assembly and search for the first data type that is a subtype of DataContext.

You could then pass that into your method:

Dim DataModel = New AttributeMappingSource().GetModel(dataContextType)

Marc