Question

I’m trying to run a Linq query on a datatable to produce a result, filtered by User and then into Date. I’m following an example of the Group By – Nested on the Linq 101 example page here.

However I wasn’t able to get it working. I’m getting a couple of errors. So I was hoping that someone would give me a hand creating the query, or at least help me get on the right track.

This is the current non-working code that I put together from the example.

var results =
                 from d in dataTableResults.AsEnumerable()
                 select new 
                    { 
                        d["DIMS User"],
                        DateGroup =
                            from o in d["Entry Date"]
                            group o by o["Entry Date"] into dg
                            select new { "Entry Date" = dg.Key, "DIMS user" = dg}
                    };

This is my DataTable Structure: (Date/Time are seperate from ShortDateToString/ShortTimetoString parse)

LogData.Columns.Add("System User", typeof(string));
LogData.Columns.Add("Host Name", typeof(string));
LogData.Columns.Add("DIMS User", typeof(string));
LogData.Columns.Add("Entry Details", typeof(string));
LogData.Columns.Add("Asset Name", typeof(string));
LogData.Columns.Add("Entry Date", typeof(string));
LogData.Columns.Add("Entry Time", typeof(string));

The errors I’m receiving are:

1) Invalid anonymous type member declarator. Anonymous type members
must be declared with a member assignment, simple name or member
access.

2) Could not find an implementation of the query pattern for source
type ‘object’. ‘GroupBy’ not found.

Lastly, Thanks for reading my post and Thanks in Advance for the help.

Answer 1

You cannot define property names of anonymous types as strings:

I have defined two classes to get your info together:

internal class Entry
{
    public string SystemUser { get; set; }
    public string HostName { get; set; }
    public string DIMSUser { get; set; }
    public string EntryDetails { get; set; }
    public string AssetName { get; set; }
    public string EntryDate { get; set; }
    public string EntryTime { get; set; }
}

internal class UserEntryPerDateInfo
{
    public string DIMSUser { get; set; }
    public string EntryDate { get; set; }
    public IEnumerable<Entry> EntryList { get; set; }
}

Here you populate your data:

IEnumerable<Entry> dataList = from d in dataTableResults.AsEnumerable()
                              select new Entry
                                {
                                    SystemUser=d["SystemUser"],
                                    HostName=d["Host Name"],
                                    DIMSUser=d["DIMS User"],
                                    EntryDetails=d["Entry Details"],
                                    AssetName=d["Asset Name"],
                                    EntryDate=d["Entry Date"],
                                    EntryTime=d["Entry Time"],
                                };

Then you group by date and user and get them in another class:

IEnumerable<UserEntryPerDateInfo> result = from a in dataList
                                           group a by new {User = a.DIMSUser, EntryDate = a.EntryDate}
                                           into grouped
                                           select
                                           new UserEntryPerDateInfo
                                           {
                                               DIMSUser = grouped.Key.User,
                                               EntryDate = grouped.Key.EntryDate,
                                               EntryList = grouped
                                           };