Field concatenation based on group in LINQ

c#, linq, wpf

Solution

You want to `GroupBy` the UserId, Date and presumably Deptname:

_context.Log.GroupBy(l => new { l.UserId, l.dates.Date, l.Deptname })
            .Select(g => new { g.Key.UserId, g.Key.Date, g.Key.Deptname, Log = string.Join(",", g.Select(i => i.times)) });

Should select the first `UserId`, `Date` and `Deptname`. Then join the log times together. Haven't checked this but seems like it should work.

Problem

I want concate a times field based on grouping of Userid and dates field using LINQ . i am using VS2010 C#(WPF). i have a collection in below format. and want result like

Original source