How do I programmatically set the connection string for Entity-Framework Code-First?

Question

I'm trying to write some code that allows me to switch between SQLCE (locally on my dev machine) and full SQL (on AppHarbor). With SQL CE, the connection string is all handled for me, but I have to construct it myself for SQL. My code so far is below, however it gives this error:

Keyword not supported: 'metadata'

I've been looking online for hours, but all the solutions involve using a "ContextBuilder" class which I can't find (I've installed EF via the NuGet package).

Here's the current code (running at startup via WebActivator):

public static void Start()
{
    // Read the details from AppSettings. Locally, these will be empty.
    var databaseHost = ConfigurationManager.AppSettings["DatabaseHost"];
    var databaseName = ConfigurationManager.AppSettings["DatabaseName"];
    var databaseUsername = ConfigurationManager.AppSettings["DatabaseUsername"];
    var databasePassword = ConfigurationManager.AppSettings["DatabasePassword"];

    // Check whether we have actual SQL Server settings.
    if (!string.IsNullOrWhiteSpace(databaseHost) && !string.IsNullOrWhiteSpace(databaseName))
    {
        // Set up connection string for a real live database :-O
        var connectionString = string.Format("metadata=res://*/DB.csdl|res://*/DB.ssdl|res://*/DB.msl;"
            + "provider=System.Data.SqlClient; provider connection string='Data Source={0};"
            + "Initial Catalog={1};User ID={2}; Password={3};MultipleActiveResultSets=True'",
            databaseHost, databaseName, databaseUsername, databasePassword);

        Database.DefaultConnectionFactory = new SqlConnectionFactory(connectionString);
    }
    else
    {
        // Set a custom database initializer for setting up dev database test data.
        Database.SetInitializer<BlogDataContext>(new BlogDataIntializer());

        // Set the connection factory for SQL Compact Edition.
        Database.DefaultConnectionFactory = new SqlCeConnectionFactory("System.Data.SqlServerCe.4.0");
    }
}

Answer 1

you should use the EntityConnectionStringBuilder class

string providerName = "System.Data.SqlClient";
string serverName = ".";
string databaseName = "AdventureWorks";

// Initialize the connection string builder for the
// underlying provider.
SqlConnectionStringBuilder sqlBuilder =
new SqlConnectionStringBuilder();

// Set the properties for the data source.
sqlBuilder.DataSource = serverName;
sqlBuilder.InitialCatalog = databaseName;
sqlBuilder.IntegratedSecurity = true;

// Build the SqlConnection connection string.
string providerString = sqlBuilder.ToString();

// Initialize the EntityConnectionStringBuilder.
EntityConnectionStringBuilder entityBuilder =
new EntityConnectionStringBuilder();

//Set the provider name.
entityBuilder.Provider = providerName;

// Set the provider-specific connection string.
entityBuilder.ProviderConnectionString = providerString;

// Set the Metadata location.
entityBuilder.Metadata = @"res://*/AdventureWorksModel.csdl|
                        res://*/AdventureWorksModel.ssdl|
                        res://*/AdventureWorksModel.msl";
Console.WriteLine(entityBuilder.ToString());

using (EntityConnection conn =
new EntityConnection(entityBuilder.ToString()))
{
conn.Open();
Console.WriteLine("Just testing the connection.");
conn.Close();
}