Question

We are building our software with Model-View-Presenter passive view strategy. On our software we have a report and different kind of charts. So we have an abstract class for chart for functions that all charts will implement:

abstract class AbstractChart
{
    ...
}

Then we have concrete classes (models), lets say BarChart and PieChart:

class BarChart: AbstractChart
{
    ...
}
class PieChart: AbstractChart
{
    ...
}

A report can contain different kind of charts.

class Report
{
    public List<AbstractChart> Charts {get; set; }
    ...
}

So, we have a problem on drawing different charts on a report:

class ReportPresenter
{
    Report _report;
    ReportView _view;
    ...
    FillReportView(Report report)
    {
        foreach(AbstractChart chart in _report.Charts)
        {
            // Here is the problem: How do we create correct
            // view and presenter for abstract chart? We need to
            // create them, so we can add chart view to _view.
        }
    }
} 

Answer 1

In lack of a better idea, I’ve solved this problem by making a Factory-class that creates an appropriate presenter for a model. For now I have the view created in their presenters, although it would be better to use an IoC-container like Unity.