I want to register a new context with a connectionstring from the configucation file.

How to do this? 

This doesn't work:

MyOwnDataContect : System.Data.Linq.DataContext

MyOwnDatacontext dataContext = new MyOwnDataContext(System.Configuration.ConfigurationManager.ConnectionString)
model.RegisterContext(dataContext, new ContextConfiguration() { ScaffoldAllTables = true });

Hi m@rco, have a look at this thread here http://forums.asp.net/p/1330279/2668877.aspx where Scott Hunter suggests

model.RegisterContext(() => new NorthwindDataContext("") , new ContextConfiguration() { ScaffoldAllTables = false });

Hope this helps

thanx for you reply!

this works, but how...

You are usually better off to pass the connection string explicitly. You can generate your various connection strings in global.asax or store them in a configuration file. The snippet below generates a connection string using integrated security and one using SQL security (each string could easily resolve to different DBs).

string conStrIntegratedSecurity = new System.Data.EntityClient.EntityConnectionStringBuilder
            {
                Metadata = "res://*/LT08.csdl|res://*/LT08.ssdl|res://*/LT08.msl",
                Provider = "System.Data.SqlClient",
                ProviderConnectionString = new System.Data.SqlClient.SqlConnectionStringBuilder
                {
                    InitialCatalog = "AdventureWorksLT2008",
                    DataSource = "bing0",
                    IntegratedSecurity = true,
                }.ConnectionString
            }.ConnectionString;


            string connectionString = new System.Data.EntityClient.EntityConnectionStringBuilder
            {
                Metadata = "res://*/LT08.csdl|res://*/LT08.ssdl|res://*/LT08.msl",
                Provider = "System.Data.SqlClient",
                ProviderConnectionString = new System.Data.SqlClient.SqlConnectionStringBuilder
                {
                    InitialCatalog = "AdventureWorksLT2008",
                    DataSource = "bing0",
                    IntegratedSecurity = false,
                    UserID = getUID(),                 // User ID such as "sa"
                    Password= getPWD(),               // hide the password
                }.ConnectionString
            }.ConnectionString;

 Now just pass in the conections string you want

 
 string conStr =  connectionString ;
        //conStr = "Data Source=ricka0;Initial Catalog=AdventureWorksLT;"
        //              + "Persist Security Info=True;User ID=sa;Password=*(IU89iu;";

        model.RegisterContext(() => new DataClassesDataContext(conStr), new ContextConfiguration() { 
            ScaffoldAllTables = true });