It is possible to use nested groups with LINQ

I have based it on the solution I found: http://stackoverflow.com/questions/6380844/group-posts-by-year-then-by-month?answertab=active#tab-top

I assumed you are using DynamicNode class which will give the following solution:

var nestedGroups = from p in newsOverview.Descendants("duhubCalendarItem").Items.OrderByDescending(x => DateTime.Parse(x.GetPropertyValue("date")))
                   group p by DateTime.Parse(p.GetPropertyValue("date")).Year into yg
                   select new {
                       Year = yg.Key,
                       Months = from o in yg
                                group o by DateTime.Parse(o.GetPropertyValue("date")).Month into mg
                                select new {
                                    Month = mg.Key,
                                    Items = mg.Select(x => x)
                                }
                   };

Which can be accessed like so:

foreach (var groupedYear in nestedGroups) {
    int year = groupedYear.Year;

    foreach (var groupedMonth in groupedYear.Months) {
        int month = groupedMonth.Month;

        foreach (var newsItem in groupedMonth.Items) {
            string name = newsItem.Name;
        }
    }
}

Do not forget to add the using at the top of the razorscript:

@using System.Linq

This should work :)

This has been super-handy lothar - thanks for posting it :)

I had to modify slightly, but it now works fantastically well:

int sourceNodeId = 1234;
var sourceNode = Umbraco.TypedContent(sourceNodeId);
var nestedGroups = from p in sourceNode.Descendants().Where(x => x.DocumentTypeAlias == "Event" && x.IsVisible()).OrderByDescending(x => x.GetPropertyValue("startDateTime"))
    group p by p.GetPropertyValue("startDateTime").Year into yg
    select new
    {
        Year = yg.Key,
        Months = from o in yg
            group o by o.GetPropertyValue("startDateTime").Month into mg
        select new
            {
                Month = mg.Key,
                Items = mg.Select(x => x)
            }
    };

Thanks for this great post but i have a query!!!! it is set for months but how to set it for the date /day

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