how to use multiple order by in LINQ?

Question

I want to use multiple order by in my query, and i am using LINQ.i am new to LINQ, i have tried the examples given on stackoverflow. but i dont know why these are not working for me , i am sure i am wrong some where. below is my situation. I got a project in which created using LINQ. I have little task to set order of column. Actually what is my task there is a column created date by which its ordering now. Now i want to use Createddate as well a sortOrder column for ordering.Below is code used for it: Code in page load method

ViewState["SortDirection"] = "desc";
ViewState["SortColumn"] = "createddate";
BindAllTopics(ViewState["SortDirection"].ToString(), ViewState["SortColumn"].ToString());

And my BindAllTopic Method is as bellow:

 protected void BindAllTopics(string SortType, string SortColumn)
{
    var LstTopics = (from topic in Dbobj.T_topic select topic).ToList();
    if (LstTopics.Count() > 0)
    {
        if (SortType == "ASC")
        {
            LstTopics = LstTopics.OrderBy(q => q.Name).ToList();
        }
        else
        {
            LstTopics = LstTopics.OrderByDescending(q => q.Name).ThenBy(q => q.SortOrder).ToList();
        }
        GrdTopics.DataSource = LstTopics.ToList();
        GrdTopics.PageSize = 25;
        GrdTopics.DataBind();

    }
    else
    {
        GrdTopics.DataSource = null;
        GrdTopics.DataBind();
        lblMsg.DisplayMessage(StatusMessages.InfoMessage, "No Topics Found.");
    }
}

I want to sort it firstly by sortorder which is of int type and then by Createddate.

Please help me..

You dont't need to create always a new List with `ToList`. Once is enough if you need it at all. — Tim Schmelter, Jul 19 '12 at 13:01
What is in the sortOrder field? A column name that has to be 'ordered by' as well? — jao, Jul 19 '12 at 13:02
And I guess you problem is, this always sorts by `Name` then `SortOrder`? What is the question? — Jodrell, Jul 19 '12 at 13:05
`Name` is not coming from Page Load, its an attribute of `topic` — Jodrell, Jul 19 '12 at 13:07
So you want to know how to convert a `string` into a `Func keySelector` that you can pass to the OrderBy extention? — Jodrell, Jul 19 '12 at 13:11

score 8 · Answer 1 · answered Jul 19 '12 at 13:04

8

you can add one more ThenBy() in trail

LstTopics.OrderByDescending(q => q.Name).ThenBy(q => q.SortOrder).ThenBy(m=>m.date)

answered Jul 19 '12 at 13:04

indiPy

7,115
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I think the OP would like the order to come from the parameter – Jodrell Jul 19 '12 at 13:15

score 3 · Accepted Answer · edited May 23 '17 at 12:06

3

If you do not want to use Dynamic Linq the following see Marc Gravell's answer below

stackoverflow:Dynamic Linq OrderBy

edited May 23 '17 at 12:06

Community

1
1

answered Jul 19 '12 at 13:47

AlanT

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HatSoft · Answer 3 · 2012-07-19T13:30:50.850

1

After correction you can achieve this by Dynamic Linq

LstTopics = LstTopics.OrderBy(SortColumn + " " +  SortType);)

edited Jul 19 '12 at 13:30

answered Jul 19 '12 at 13:05

HatSoft

10,683
3
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I think the OP would like the order to come from the parameter – Jodrell Jul 19 '12 at 13:15
@Jodrell I have corrected the answer thanks for pointing it out – HatSoft Jul 19 '12 at 13:23
@raman please see my updated answer you can achieve it by dynamic linq – HatSoft Jul 19 '12 at 13:24
I understand the down vote button is very attractive but please explain why down vote – HatSoft Jul 19 '12 at 13:30

how to use multiple order by in LINQ?

3 Answers3