public class CollectionItemBase
{
    public Data MyData { get; set; }
    public abstract System.Web.UI.Control GetControl();
}
public class Cat : CollectionItemBase
{
    public override Control GetControl()
    {
        Label l = new Label();
        l.Text = "Кошка по имени " + MyData.Name;
        return l;
    }
}
public class Dog : CollectionItemBase
{
    public override Control GetControl()
    {
        Label l = new Label();
        l.Text = "Собака по имени " + MyData.Name;
        return l;
    }
}
public class Data
{
    public string  Name { get; set; }
}

public class Test
{
    public Table GetTable(System.Collections.Generic.List<CollectionItemBase> list)
    {
        Table t = new Table();
        foreach (CollectionItemBase item in list)
        {
            TableRow tr = new TableRow();
            t.Rows.Add(tr);
            TableCell tc = new TableCell();
            tc.Controls.Add(item.GetControl());
            tr.Cells.Add(tc);
        }
    }
}