Group By from DataTable using linq

Question

Hi all I am having a result set as follows

    ID      Name     Price
     1      XYZ       10
     2      ABC       10
     1      ABC       20

I would like to perform group by so that it should give me

    ID      Name     Price
     1      XYZ       10
            ABC       20
     2      ABC       10

I tried with the solution form the links but I couldn't get DataTable linq query to group by a column can some one help me

Answer 1

You can do something as simple as this

context.Table.GroupBy(t => t.ID);

This will return something of this type IQueryable<IGrouping<int, YourClass>> (assuming your ID is an int)

Each entry will have a Key (the ID in this case) and an Enumerator so you can go through all the records grouped

Answer 2

Unless you want to change the original objects, you're going to have to project to a new collection and remove the repeated ID values. Something like:

var query = 
    data.GroupBy(d => d.ID)
        .OrderBy(g => g.Key)
        .SelectMany(g => (new[] {new {
                                      g.First().ID, 
                                      g.First().Name, 
                                      g.First().Price}})
                         .Concat(g.Skip(1).Select(i => new {
                                                            ID = (string)null, 
                                                            i.Name, 
                                                            i.Price})));

essentially:

• Group by ID
• Take all values of the first item in each group
• Take all values except Id for all other items in the group