C# grouping loses row

Question

I have got the following SQL-Table:

---------------------------------------------------
| ID | Line1    | Line2  | Line3  | Line4 | Line5 |
---------------------------------------------------
| 1  | Software | Citrix | XenApp | Null  | Null  |
---------------------------------------------------
| 2  | Software | Citrix | XenApp | Null  | Null  |
---------------------------------------------------

I used this code in order to group it by Line3:

var KategorienLine3 = result.GroupBy(x => x.Line3).ToList();

In which result represents the list including the 2 entries. Now this grouping results in this output:

[0] -> Key = XenApp
[1] -> Key = XenApp

But I don't have access to Line2. I would like to include it in the result. How can I do that, so that I have access to that as well? It don't want to group by it!! I just want to have it in the result.

Thats what it gives me after the grouping. I want to include Line2 as well.

You will have to group by Line2 as well (in addition to Line3). — hatchet - done with SOverflow, May 05 '17 at 18:39
result.GroupBy(x => x.Line3, x => x.Line2).ToList(); I tried this, but it still shows nonly the key... @hatchet — Tom el Safadi, May 05 '17 at 18:40
What is the way you want to see that data after the grouping — Gilad Green, May 05 '17 at 18:41
Let me append a screenshot, I want to see the "Citrix" as well. — Tom el Safadi, May 05 '17 at 18:42
Also - all data besides id is identical - is it really like that, duplicated data, or just in the given example — Gilad Green, May 05 '17 at 18:43
@Anokrize - it will make it easier if you show a better example of the data and then also what is the expected output (and remember that when grouping then each key has several items for it) — Gilad Green, May 05 '17 at 18:45
The expected output should be: Line2 -> Citrix, Line3 -> XenApp — Tom el Safadi, May 05 '17 at 18:47
@Anokrize see the answer to this question regarding grouping on multiple columns. Note the use of anonymous type. http://stackoverflow.com/questions/847066/group-by-multiple-columns — hatchet - done with SOverflow, May 05 '17 at 18:54
The result of `GroupBy` is a `IGrouping` which it's itself an `IEnumerable`. So the `Key` will be `Line3` and you would iterate over the rows in the group to get the other columns like `KategorienLine3[0].Select(r => r.Line2).ToList()`. — juharr, May 05 '17 at 18:55

Gilad Green · Accepted Answer · 2017-05-05T18:58:18.540

The data is there. It is just in the IGrouping<TKey, TResult> object returned by the GroupBy. The reason you don't have access to Line2 is that each grouping contains a collection of records that are of that group - and each record there is of your object's type, and has the Line2 property.

To retrieve it project the data as you want it to show:

// method syntax
var result  = data.GroupBy(key => key.Line3, item => item.Line2)
                  .Select(g => new
                  {
                      g.Key,
                      Line2 = g.ToList()
                  }).ToList();

// query syntax
var result = from item in data
             group item.Line2 by item.Line3 into g
             select new
             {
                 g.Key,
                 Line2 = g.ToList()
             };

C# grouping loses row

1 Answers1