How Can I Concat Three List Or Ienumerable?

Question

1.00/5 (1 vote)

See more:

C#

var datasource = new NORTHWNDEntities().Categories.ToList();
       var datasource1 = new NORTHWNDEntities().Customers.ToList();
       var datasource2 = new NORTHWNDEntities().Orders.ToList();

Posted 12-Jun-14 20:19pm

ilaya muthumanickam

Add a Solution

Comments

Sergey Alexandrovich Kryukov 13-Jun-14 2:25am

What does "concat" mean? What have you tried so far?
—SA

Debabrata_Das 13-Jun-14 3:05am

Did you mean merging three lists into a single object?

ilaya muthumanickam 13-Jun-14 3:35am

yes absolutely /var Datasource = datasource.Concat(datasource1)Concat(datasource2);
i tried this one But it's not apt....

Debabrata_Das 13-Jun-14 3:53am

If you want to merge the above three data source into a single List (in a single column) then solution provided by Manikanandan10 will solve your problem.

ilaya muthumanickam 13-Jun-14 4:39am

yes please help me

johannesnestler 13-Jun-14 7:20am

Hi,

Maybe you tell us what you want to achieve. Your code doesn't make sense because you want to "concat" (whatever that means) different types - Customers, Orders, Catergories as list? - did you mean some kind of joining?. Anyway, It would be clearer if you tell us what type your "datasoucre" should have in the end. IEnumerable<object> or IEnumearable<isomecommoninterface> an anonymous type, what? After that generating your "list" should be straight forwards, but I'd question your requirement first...

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Manikandan10 · Answer 1 · 2014-06-12T21:31:00

Solution 1

See the following code:

C#

class Program
{
    static void Main(string[] args)
    {
        List<int> a = new List<int>();
        a.Add(1);
        a.Add(2);

        List<int> b = new List<int>();
        b.Add(3);
        b.Add(4);

        List<int> c = new List<int>();
        c.Add(5);
        c.Add(6);

        List<int> concat = new List<int>(a.Concat(b).Concat(c));

        for (int i = 0; i < concat.Count; ++i)
        {
            Console.WriteLine(concat[i]);
        }
        Console.ReadKey();
    }
}

Posted 12-Jun-14 21:31pm

Manikandan10

Comments

ilaya muthumanickam 13-Jun-14 4:52am

Thanks for your reply Manikandan. But i need to concatenate three Ienumarable

public ActionResult Index()
{

var datasource = new NORTHWNDEntities().Categories.ToList();
var datasource1 = new NORTHWNDEntities().Customers.ToList();
var datasource2 = new NORTHWNDEntities().Orders.ToList();

var Datasource = datasource.Concat(datasource1).Concat(datasource2);

ViewData["datasource"] = Datasource;

return View();
}

Error 'System.Collections.Generic.List<syncfusionexample.models.employee>' does not contain a definition for 'Union' and the best extension method overload 'System.Linq.Queryable.Union<tsource>(System.Linq.IQueryable<tsource>, System.Collections.Generic.IEnumerable<tsource>)' has some invalid arguments C:\Users\Administrator\Desktop\setup .net 3.5\EJ sample\SyncFusionExample\SyncFusionExample\Controllers\HomeController.cs 62 30 SyncFusionExample

[no name] 13-Jun-14 8:53am

Where exactly are you getting this error? If datasource, datasource1, datasource2 are IEnumerable, then the line
var Datasource = datasource.Concat(datasource1).Concat(datasource2);
should not produce any error. See Solution 2.

Manikandan10 · Answer 2 · 2014-06-13T03:03:00

In your code,

C#

var datasource = new NORTHWNDEntities().Categories.ToList();
var datasource1 = new NORTHWNDEntities().Customers.ToList();
var datasource2 = new NORTHWNDEntities().Orders.ToList();

If these three lines are correct and datasource, datasource1 and datasource2 are IEnumerable then your code shouldn't produce any error. Are you getting the error in this line?

C#

ViewData["datasource"] = Datasource;

Does new NORTHWNDEntities().Categories.ToList(); returns a IEnumerable, then your code shouldn't produce errors.

And to concat three IEnumberables, the following code works(a modification of code in Soln 1):

C#

List<int> a = new List<int>();
a.Add(1);
a.Add(2);

List<int> b = new List<int>();
b.Add(3);
b.Add(4);

List<int> c = new List<int>();
c.Add(5);
c.Add(6);

IEnumerable<int> a2 = a.Cast<int>();
IEnumerable<int> b2 = b.Cast<int>();
IEnumerable<int> c2 = c.Cast<int>();

IEnumerable<int> concat = a2.Concat(b2).Concat(c2);

And also, don't use var always. I'm not against var, but you should know the type of the object before you use it.