take top 10 or 20 rows from dynamic datatable

Question

I have 100 records in my Datable says to be in

DataTable dt=new DataTable();

dt have 100 of records say column name as sub_id(contain int datatype) and subheadername(contain nvarchar(150)) , I want top 20 records from this dt in ascending order

I am putting code as

//dtlcategories.DataSource = dt.AsEnumerable().OrderBy(x => x["subheadername"]).Take(20).ToList();
dtlcategories.DataSource = dt.Rows.Cast<DataRow>().OrderBy(x => x["subheadername"]).Take(20).ToList();
dtlcategories.DataBind();

Here dtlcategories is Datalist but on running error is coming as 'System.Data.DataRow' does not contain a property with the name 'subheadername'.

ANSWER IS SOLVED

dtlcategories.DataSource = dt.Rows.Cast<DataRow>().OrderBy(x => x["subheadername"]).Take(20).copytodatatable();
dtlcategories.DataBind();

http://stackoverflow.com/questions/10855/linq-query-on-a-datatable — trinaldi, Dec 21 '13 at 11:30

Grant Winney · Accepted Answer · 2013-12-21T12:59:00.353

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There's a couple different ways you can do this using LINQ. These will both return the same results.

dt.AsEnumerable().OrderBy(x => x["subheadername"]).Take(20);

dt.Rows.Cast<DataRow>().OrderBy(x => x["subheadername"]).Take(20);

If you're going to use the result as the source of data for another control, you may need to call .ToList() after .Take(x).

Edit:

I changed the column name based on your edit. If you want to sort by id instead (you didn't specify), just replace "subheadername" with "sub_id".

edited Dec 21 '13 at 12:59

answered Dec 21 '13 at 11:34

Grant Winney

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Please see my edited question and edit your answer as per my column name and in orderby ascending – Dec 21 '13 at 12:28
how should i take this value in my datalist.datasource?? – Dec 21 '13 at 12:39
i am putting like ... dt.AsEnumerable().OrderBy(x => x["subheadername"]).Take(20).ToList(); dtlcategories.DataSource = dt.Rows.Cast().OrderBy(x => x["subheadername"]).Take(20).ToList();....butt error is coming as 'System.Data.DataRow' does not contain a property with the name 'subheadername'. – Dec 21 '13 at 12:57
i have edited my question, please made me know whats my mistake?? – Dec 21 '13 at 13:02
If i used to put sub_id than error as "System.Data.DataRow' does not contain a property with the name 'sub_id " – Dec 21 '13 at 13:12

Ondrej Janacek · Answer 2 · 2013-12-21T12:31:45.667

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This query fetches top 20 records from db and then orders them by the sub_id column.

var topTwenty = dt.AsEnumerable().Take(20).OrderBy(r => r.Field<int>("sub_id"));

edited Dec 21 '13 at 12:31

answered Dec 21 '13 at 11:34

Ondrej Janacek

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@GrantWinney That's the way I understand the question, though. – Ondrej Janacek Dec 21 '13 at 12:08
Please see my edited question and edit your answer as per my column name and in orderby ascending – Dec 21 '13 at 12:29
if i want to order this on subheadername than i used to take nvarchar(150) in place of int??? – Dec 21 '13 at 12:34
@Xtremcool no, C# does not recognize `nvarchar(150)` as a type, you have to use `string` instead – Ondrej Janacek Dec 21 '13 at 12:37
i am getting error "System.InvalidCastException: Specified cast is not valid."...when i used to fill this record in my datalist tool like dtlcategories.DataSource = dt.AsEnumerable().Take(20).OrderBy(r => r.Field("sub_id")); dtlcategories.DataBind(); – Dec 21 '13 at 12:38
try appending `.Cast()` as in the Grant Winney's answer – Ondrej Janacek Dec 21 '13 at 12:39
i have edited my question, please made me know whats my mistake?? – Dec 21 '13 at 13:02
you have "sibheadername" instead of "subheadername" – Ondrej Janacek Dec 21 '13 at 13:04

Arindam · Answer 3 · 2013-12-21T12:55:10.163

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dt.AsEnumerable().OrderBy(row => row["sub_id"]).Take(20);

This will return you IEnumerable. Now iterate through the IEnumerable and add them to another data table. Now your final data table is ready!!

edited Dec 21 '13 at 12:55

answered Dec 21 '13 at 11:36

Arindam

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Please see my edited question and edit ypur answer as per my column name – Dec 21 '13 at 12:27

SHM · Answer 4 · 2013-12-21T13:15:00.327

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this code orders data according to date and takes first 100 row.

 var table = new DataTable();
 var t = table.AsEnumerable();
 var result = t.OrderByDescending(f => f.Field<DateTime>(new DataColumn("Date"))).Take(100);

Update:

var table = new DataTable();
var t = table.AsEnumerable();
var result = t.OrderBy(f => f.Field<String>(new DataColumn("subheadername"))).Take(20)

edited Dec 21 '13 at 13:15

answered Dec 21 '13 at 11:44

SHM

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Please see my edited question and edit your answer as per my column name and in orderby ascending – Dec 21 '13 at 12:29

score 0 · Answer 5 · edited Dec 21 '13 at 12:53

0

A possible solution:

DataRow[] rows = dt.Select("sub_id< 100 ");

edited Dec 21 '13 at 12:53

Rubens

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answered Dec 21 '13 at 11:34

Vignesh Kumar A

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Please see my edited question and edit ypur answer as per my column name – Dec 21 '13 at 12:26

take top 10 or 20 rows from dynamic datatable

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