CODEWITHSUNDEEP
c#linq
webdad3
webdad3

Reputation: 9080

create object from LINQ

I have an object:

public class DataItem
{

    public string Location
    {
        get;
        set;
    }

    public List<string> PersonList
    {
        get;
        set;
    }
}

I have some results from a table that return something like:

Room1 John
Room1 Jim
Room1 Dawn
Room1 Bob
Room1 Katie

I have some LINQ that I've written:

var grouped = from table in sqlResults.AsEnumerable()
              group table by new { placeCol = table["LOCATION"] } into groupby
              select new
              {
                  Value = groupby.Key,
                  ColumnValues = groupby
              };

Which groups my results... But I'd like to put this into my object (DataItem). I've seen a couple of examples but nothing has worked... What am I missing?

Upvotes: 0

Views: 7334

Answers (5)

Dude0001
Dude0001

Reputation: 3450

Since in your sample data (of DataItem's?) only includes one person in each Location, I'm questioning if the PersonList property on your DataItem class should really be just a single Person (or "string" in your example). It looks like you are querying a list of people and their location, and then trying to group those results by location and list each person in that location. I think you are trying to create something like a Lookup.

Look at this code.

public class DataItem
{

     public string Location
     {
         get;
         set;
     }

     public string Person
     {
         get;
         set;
     }
 }

 // omitted fetch of sqlResults

 var grouped = sqlResults.AsEnumerable()
      .ToLookup(
           item => new
           {
                Location = item.Location
           }),
           item => new
           {
                Person = item.Person
           });

Or maybe you are trying to stuff the results of the LINQ query into your original DataItem. If you are only accessing the grouped variable within the scope of the method, you can just use the inferred type. Otherwise, one of the other answers are correct.

Upvotes: 0

Servy
Servy

Reputation: 203829

  1. Don't group on a new anonymous object with a single value representing your location, just group on the location

  2. Don't select a new anonymous object as the result, select the object you care about

  3. Select out the person name from the group when getting the person list.

var grouped = from row in sqlResults.AsEnumerable()
                group row by row.Field<string>("LOCATION") into groupby
                select new DataItem()
                {
                    Location = groupby.Key,
                    PersonList = groupby.Select(row => 
                        row.Field<string>("Person")).ToList();
                };

Upvotes: 3

Matan Shahar
Matan Shahar

Reputation: 3240

You only need the initialize a new instance of DataItem, ie:

select new DataItem
          {
              Location = groupby.Key,
              PersonList = groupby.ToList()
          };

the idea of select is to select / return an instance for each iteration of the expression so you just need the specify what you want to return. (When use only new you're actually initializing a new anonymous type).

Upvotes: 0

Tigran
Tigran

Reputation: 62246

May be something like: 

 select new DataItem
   {
     Location= groupby.Key,
     PersonList = groupby
   };

Note, that in this case you have to declare PersonList as IEnumerable<string>

Upvotes: 0

MarcinJuraszek
MarcinJuraszek

Reputation: 125630

Change your select clause. You also don't need to use anonymous object as a grouping key, because you use only one value as a key.

var grouped = from table in sqlResults.AsEnumerable()
              group table by table["LOCATION"] into groupby
              select new DataItem
              {
                  Location = groupby.Key,
                  PersonList = groupby.ToList()
              };

Upvotes: 0

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