Update 2009-03-03: Darren Green has a post which covers the other configuration types as well.

This sample programmatically adds a reference to an existing configuration file to a package.

Things to note:

• The CreatePackage() method just creates a package (it doesn’t matter what is in it). Typically you’d be using this code to add a configuration to an existing package (doing a Package.LoadFromXml() or something similar)
• For this approach to work, the paths in the configuration file must be the same in every package.

class ConfigurationReference
{
    static void Main(string[] args)
    {
        //
        // Add a reference to an existing configuration file.
        // Note all property paths must match.
        //
        Package package = CreatePackage();

        // Enable configurations
        package.EnableConfigurations = true;

        // Create the configuration reference
        Configuration config = package.Configurations.Add();
        config.Name = "Configuration";
        config.ConfigurationType = DTSConfigurationType.ConfigFile;
        config.ConfigurationString = @"c:\temp\config.dtsconfig";
    }

    static Package CreatePackage()
    {
        var p = new Package();

        // Add Data Flow Task
        Executable dataFlowTask = p.Executables.Add("STOCK:PipelineTask");

        // Set the name (otherwise it will be a random GUID value)
        var taskHost = dataFlowTask as TaskHost;
        Debug.Assert(taskHost != null, "Unexpected task type");

        taskHost.Name = "Data Flow Task";

        // We need a reference to the InnerObject to add items to the data flow
        var pipeline = taskHost.InnerObject as MainPipe;
        Debug.Assert(pipeline != null, "Unexpected InnerObject type");

        // Create a package variable to store the row count value
        p.Variables.Add("RowCountVar", false, "User", 0);

        // Add connection manager
        ConnectionManager connection = p.Connections.Add("OLEDB");
        connection.Name = "MyConnection";
        connection.ConnectionString = "Data Source=localhost;Initial Catalog=AdventureWorksDW2008;Provider=SQLNCLI10.1;Integrated Security=SSPI;Auto Translate=False;";

        // Add OLEDB Source
        IDTSComponentMetaData100 srcComponent = pipeline.ComponentMetaDataCollection.New();
        srcComponent.ComponentClassID = "DTSAdapter.OleDbSource";
        srcComponent.ValidateExternalMetadata = true;
        IDTSDesigntimeComponent100 srcDesignTimeComponent = srcComponent.Instantiate();
        srcDesignTimeComponent.ProvideComponentProperties();
        srcComponent.Name = "OleDb Source";

        // Configure it to read from the given table
        srcDesignTimeComponent.SetComponentProperty("AccessMode", 0);
        srcDesignTimeComponent.SetComponentProperty("OpenRowset", "[DimCustomer]");

        // Set the connection manager
        srcComponent.RuntimeConnectionCollection[0].ConnectionManager = DtsConvert.GetExtendedInterface(connection);
        srcComponent.RuntimeConnectionCollection[0].ConnectionManagerID = connection.ID;

        // Retrieve the column metadata
        srcDesignTimeComponent.AcquireConnections(null);
        srcDesignTimeComponent.ReinitializeMetaData();
        srcDesignTimeComponent.ReleaseConnections();

        // Add Row Count transform
        IDTSComponentMetaData100 rowCount = pipeline.ComponentMetaDataCollection.New();
        rowCount.ComponentClassID = "DTSTransform.RowCount";
        CManagedComponentWrapper instance = rowCount.Instantiate();
        instance.ProvideComponentProperties();

        // Set the variable name property
        instance.SetComponentProperty("VariableName", "User::RowCountVar");

        // Connect the OLEDB Source and the Row Count
        IDTSPath100 path = pipeline.PathCollection.New();
        path.AttachPathAndPropagateNotifications(srcComponent.OutputCollection[0], rowCount.InputCollection[0]);

        return p;
    }
}