过滤三个列表的优雅方式

Question

我在一个页面上工作，用户可以在其中过滤展示事件列表。为此，他们可以从三个标准中进行选择：月份，位置，事件名称。

对于每个条件，通过jquery ajax创建并发布字符串数组。降低数组，然后筛选show事件列表：

            if (loweredAndTrimmedDates != null)
            {
                listFilteredByDates = new List<Performance>();
                listFilteredByDates = performanceList.Where
                    (
                        performance =>
                            loweredAndTrimmedDates.Contains(performance.Datum.Value.ToString("MMMM", CultureInfo.DefaultThreadCurrentCulture).ToLower().Trim())
                    ).ToList();

                if (loweredAndTrimmedLocations != null)
                {
                    listFilteredByLocations = new List<Performance>();
                    listFilteredByLocations = listFilteredByDates.Where
                        (
                            performance =>
                                loweredAndTrimmedLocations.Any(location => location.Equals(performance.Location.Name.ToLower().Trim() + ", " + performance.Location.Stadt.ToLower().Trim()))
                        ).ToList();

                    if (loweredAndTrimmedEvents != null)
                    {
                        listFilteredByEvents = new List<Performance>();
                        listFilteredByEvents = listFilteredByLocations.Where
                            (
                                performance =>
                                    loweredAndTrimmedEvents.Any(evnt => evnt.Contains(performance.Event.Name.ToLower().Trim()))
                            ).ToList();

                        return listFilteredByEvents.OrderBy(p => p.Datum);
                    }
                    else
                    {
                        return listFilteredByLocations.OrderBy(p => p.Datum);
                    }
                }
                else
                {
                    if (loweredAndTrimmedEvents != null)
                    {
                        listFilteredByEvents = new List<Performance>();
                        listFilteredByEvents = listFilteredByDates.Where
                            (
                                performance =>
                                    loweredAndTrimmedEvents.Any(evnt => evnt.Contains(performance.Event.Name.ToLower().Trim()))
                            ).ToList();

                        return listFilteredByEvents.OrderBy(p => p.Datum);
                    }
                    else
                    {
                        return listFilteredByDates.OrderBy(p => p.Datum);
                    }
                }
            }
            else
            {
                if (loweredAndTrimmedLocations != null)
                {
                    listFilteredByLocations = new List<Performance>();
                    listFilteredByLocations = performanceList.Where
                        (
                            performance =>
                                loweredAndTrimmedLocations.Any(location => location.Equals(performance.Location.Name.ToLower().Trim() + ", " + performance.Location.Stadt.ToLower().Trim()))
                        ).ToList();

                    if (loweredAndTrimmedEvents != null)
                    {
                        listFilteredByEvents = new List<Performance>();
                        listFilteredByEvents = listFilteredByLocations.Where
                            (
                                performance =>
                                    loweredAndTrimmedEvents.Any(evnt => evnt.Contains(performance.Event.Name.ToLower().Trim()))
                            ).ToList();

                        return listFilteredByEvents.OrderBy(p => p.Datum);
                    }
                    else
                    {
                        return listFilteredByLocations.OrderBy(p => p.Datum);
                    }
                }
                else
                {
                    if (loweredAndTrimmedEvents != null)
                    {
                        listFilteredByEvents = new List<Performance>();
                        listFilteredByEvents = performanceList.Where
                            (
                                performance =>
                                    loweredAndTrimmedEvents.Any(evnt => evnt.Contains(performance.Event.Name.ToLower().Trim()))
                            ).ToList();

                        return listFilteredByEvents.OrderBy(p => p.Datum);
                    }
                    else
                    {
                        return performanceList.OrderBy(p => p.Datum);
                    }
                }
            }

对于那些不想阅读该代码段的人： 我正在检查一个数组是否为空。如果没有，事件将被存储在数组中的选项过滤，然后我跳到下一个数组并检查它是否为空等等。每个步骤都使用先前过滤的事件列表。

我认为这不是一种优雅的方式。但我不知道如何做得更好。

你能否告诉我如何用这个代码生成更好，更精简和更易读的代码？