public class RsDataDeclarationCollection : ICollection, 
	IEnumerable, IEnumerable<RsDataDeclaration>

Project.UndoContext.BeginUndoStep("RsDataDeclarationCollection");
try
{
    Station station = Station.ActiveStation;

    // Get the RsDataDeclarationCollection for the ActiveTask.
    RsDataDeclarationCollection ddCol = station.ActiveTask.DataDeclarations;
    RsRobTarget rbt = new RsRobTarget();
    rbt.Name = station.ActiveTask.GetValidRapidName("MyRobTarget", "_", 1);
    String robTargetName = rbt.Name;
    ddCol.Add(rbt);

    // Output some info of the DataDeclaration in the logger.
    Logger.AddMessage(new LogMessage("The RsDataDeclarationCollection on the active task contains:"));
    foreach (RsDataDeclaration dd in ddCol)
    {
        Logger.AddMessage(new LogMessage("DataDeclaration: " + dd.Name + " with type: " + dd.TypeDisplayName));
    }

    // Check that RsDataDeclarationCollection contains the RobTarget that was added.
    if (station.ActiveTask.FindDataDeclarationFromModuleScope(robTargetName, rbt.ModuleName) != null)
    {
        Logger.AddMessage(new LogMessage("The RsDataDeclarationCollection contains " + robTargetName));
    }
    RsDataDeclaration rbt2;
    try
    {
        rbt2 = station.ActiveTask.FindDataDeclarationFromModuleScope("MyRobTarget_2", rbt.ModuleName);
        if (rbt2 != null)
        {
            Logger.AddMessage(new LogMessage("Found MyRobTarget_2"));
        }
        else
        {
            Logger.AddMessage(new LogMessage("Did not find MyRobTarget_2"));
        }
    }

    catch (ArgumentException e)
    {
        Logger.AddMessage(new LogMessage("The error: '" + e.Message + "' occured when trying to get 'MyRobTarget_2'"));
    }

    // Remove MyRobTarget_1 from the collection.
    ddCol.Remove(rbt);
}
catch
{
    Project.UndoContext.CancelUndoStep(CancelUndoStepType.Rollback);
    throw;
}
finally
{
    Project.UndoContext.EndUndoStep();
}