Need help with Linq

Question

I have a sample class like this:

SampleClass
{
    string code;
    int id;
    string name;    
}

Valid data for the class would be:

SampleClass{code= "code1", id= 1, name= "name1"}
SampleClass{code= "code1", id= 1, name= "name2"}
SampleClass{code= "code2", id= 2, name= "name1"}
SampleClass{code= "code2", id= 2, name= "name2"}
SampleClass{code= "code2", id= 2, name= "name3"}

Now the question is, by using LINQ, I need to create a TestClass collection grouped on the SampleClass "id" field.

TestClass structure is as follows:

TestClass
{
    string code;        
    List<string> names;    
}

where "names" is a list of all SampleClass "name" values grouped by "id".

Based on the above SampleClass sample data, I would have 2 TestClass objects, one for id=1 and other for id=2

Thanks in advance

Answer 1

var result = from c in collection
             group c by c.id into g
             select new TestClass {
                                      code = g.First().code,
                                      names = g.Select(i => i.name).ToList()
                                  };

ps: I have no VS near now, and I hope I did not make a lot of mistakes there :-)

Answer 2

MSDN has some great LINQ examples, including using the Grouping to do just what you need. You can find an example doing something similar to what you want here.

Answer 3

OK, if you have an IEnumerable of SampleClasses called classes, try this:

        var testClasses = classes
            .GroupBy(c => c.id)
            .Select(grp => new TestClass
            {
                code = grp.First().code,
                names = grp.Select(c => c.name).ToList()
            });