Science Project

re: Science Project

Moristar — Sat, 08 Sep 2007 10:22:42 GMT

Great thanks!!! This is good way!

re: Science Project

rogerj — Sat, 08 Sep 2007 20:33:28 GMT

Pingback from http://oakleafblog.blogspot.com/2007/09/linq-and-entity-framework-updates-for.html.

re: Science Project

rogerj — Sat, 08 Sep 2007 22:19:07 GMT

Sorry, entry moved to http://oakleafblog.blogspot.com/2007/09/linq-and-entity-framework-posts-for.html

--rj

re: Science Project

akula — Sun, 09 Sep 2007 08:02:40 GMT

This is great and was exactly what I needed. I do get an parameter mismatch error in

foreach (PropertyInfo p in pi)

{

values[_ordinalMap[p.Name]] = p.GetValue(instance,null);

}

if I use:

var a = (from m_var in dc.Ptabs

select m_var.CAR ).Distinct();

DataSet ds = new DataSet();

ds.Tables.Add(a.CopyToDataTable());

but not if I do this

var a = (from m_var in dc.Ptabs

select new { Car = m_var.CAR }).Distinct();

DataSet ds = new DataSet();

ds.Tables.Add(a.CopyToDataTable());

re: Science Project

aconrad — Tue, 11 Sep 2007 04:50:40 GMT

thanks - there are a couple of problems here:

1) The code is not catching the error case when the type T of the source sequence does not match the schema of the provided datatable. I suppose I could extend the table automatically in this case.

2) The results of your query is just a sequence of scaler values. The code wasn't really designed for this and I am not sure I see much value, but I suppose I could just make a table with a single column.

I will update the sample code to fix these issues.

re: Science Project

akula — Wed, 12 Sep 2007 09:25:20 GMT

Thanks

re: Science Project

jonm — Wed, 19 Sep 2007 15:46:32 GMT

This seems very helpful, is there a straightforward way to implement in vb.net?

re: Science Project

Neeta — Mon, 26 Nov 2007 23:10:41 GMT

Hi, this post was helpful.

However it seems to have problem when used with nullable types.

I am using LINQ to SQL data context calss to store data base tables.Then I query these tables and get result of type "var" and then convert it to datatable using this code.

Some of the tables are of nullable type.So while conversion I receive an error saying "DataSet does not support System.Nullable<>"

inside the ExtendTable method, when the code tries to add columns to the "table"

Pls let me know if you have any suggestions/workaround to this problem.

Thanks in advance

Regards,

Neeta

re: Science Project

aconrad — Tue, 11 Dec 2007 09:32:34 GMT

ah - I will try to get the code working with nullable types over the holidays.

re: Science Project

Nick Lucas — Wed, 19 Dec 2007 14:08:36 GMT

Change the code to be this in order to handle nullable types:

foreach (PropertyInfo p in type.GetProperties())

{

if (!_ordinalMap.ContainsKey(p.Name))

{

Type colType = p.PropertyType;

if ((colType.IsGenericType) && (colType.GetGenericTypeDefinition() == typeof(Nullable<>)))

{

colType = colType.GetGenericArguments()[0];

}

DataColumn dc = table.Columns.Contains(p.Name) ? table.Columns[p.Name]

: table.Columns.Add(p.Name, colType);

_ordinalMap.Add(p.Name, dc.Ordinal);

}

re: Science Project

adefwebserver — Fri, 28 Dec 2007 00:43:53 GMT

Wow thank you so much! This allows me to use a LINQ query in my DAL and then bind an Object Data Source control to it. Then I can bind the GridView to the Object Data Source control and turn on sorting and paging and it all works!

re: Science Project

Yigit Ozmen — Wed, 09 Jan 2008 12:13:02 GMT

Thank you all.Is there a VB version of the complete code anywhere else?Any help appreciated much.

re: Science Project

eyunni — Thu, 10 Jan 2008 00:01:04 GMT

I am trying to use the above idea to convert entities into datatables. However, the linq query does not expose the CopyToDataTable() method. Am I missing something here?

re: Science Project

Andrew Conrad — Fri, 11 Jan 2008 21:42:29 GMT

Make sure you use the namespace the you defined the DataSetLinqOperators in.

Pathetic Plea for help

Man vs Code — Fri, 11 Jan 2008 22:12:17 GMT

A number of people have asked me for a VB version of the CopyToDataTable<T> sample I wrote a few

Pathetic Plea for help

Noticias externas — Fri, 11 Jan 2008 22:54:25 GMT

A number of people have asked me for a VB version of the CopyToDataTable<T> sample I wrote a few

re: Science Project

Ming — Wed, 16 Jan 2008 13:35:54 GMT

I cannot find any CopyToDataTable() method......

btw, i think if we just want a datatable , using the code above is

sooooooooooooo complex.

re: Science Project

Viper — Tue, 22 Jan 2008 20:09:20 GMT

Awesome.

I added in the change for Nullable types by Nick and the whole thing is working beautifully. Only thing of note is that I had to change the method names due to a conflict. I am going to check that out.

Cheers.

LINQ CopytoDataTable in C# and in VB

Hot Topics — Tue, 22 Jan 2008 23:14:19 GMT

There was a CopytoDataTable method in early betas of LINQ but then it disappeared. C#: Andy Conrad on

re: Science Project

boomhauer — Thu, 07 Feb 2008 00:01:39 GMT

any code out there that can help load a dlinq object FROM a datatable? Im workin with webservices and still passing datasets, so would like to load up a bunch of dlinq entities from the datatables and commit them to the db... probably easier to just use the datatables, i guess...

实现CopyToDataTable

works guo — Wed, 16 Apr 2008 18:55:41 GMT

LINQ to DataSet中实现CopyToDataTable

LinQ to StimulReport ? lol (Part 1)

Desenvolvimento — Thu, 17 Apr 2008 23:53:28 GMT

A utilização do LinQ em projetos dentro do TJMT forçou uma estrutura de projeto, mas ainda não estamos

re: Science Project

Alex Sarafian — Wed, 23 Apr 2008 11:19:35 GMT

I was looking the same thing.

I tried the above solution but for various reasons I was not satisfied.

One of the biggest reasons was that I like using Typed Datasets.

So I tried to create my own convertion method.It stated as a proof o concept and later became something that could be done.

Here is the solution I propose

http://sarafianalex.wordpress.com/2008/04/21/typed-dataset-linq-entities/

re: Science Project

Ed Staffin — Fri, 25 Jul 2008 02:54:46 GMT

Hi,

There seems to be a problem with the ExtendTable routine and I'm not sure how to solve it. In the routine ExtendTable there is the following code:

For Each p As PropertyInfo In type.GetProperties()

If Not _ordinalMap.ContainsKey(p.Name) Then

Dim colType As Type = p.PropertyType

If (colType.IsGenericType) AndAlso (colType.GetGenericTypeDefinition() Is GetType(Nullable(Of ))) Then

colType = colType.GetGenericArguments()(0)

End If

Dim dc As DataColumn = IIf(table.Columns.Contains(p.Name), table.Columns(p.Name), table.Columns.Add(p.Name, colType))

_ordinalMap.Add(p.Name, dc.Ordinal)

End If

The issue seems to be that type.GetProperties() returns the columns in alphabetical order instead of the order returned from the query. Can anyone offer some ideas on how to get them back in the right order. Or, at least to be able to contruct the datatable with the columns in the right order.

Thanks ... Ed

re: Science Project

Scott Kleinert — Thu, 06 Nov 2008 23:07:08 GMT

I'm having the same issue as Ed. Has anyone figured how to return columns in the same order as the query?

Thanks,

Scott

re: Science Project

Scott Kleinert — Thu, 20 Nov 2008 23:55:34 GMT

A note on the column order...I've noticed that on my vista laptop, the order of the columns is returned as expected. On my XP desktop, the columns are returned alphabetically. Still don't know why...though it might help someone smarter than I.

Scott

re: Science Project

Scott Kleinert — Thu, 20 Nov 2008 23:55:40 GMT

Scott

Doesn't compile on VS 2008

Nikolay Sonin — Fri, 14 Aug 2009 00:25:57 GMT

For me it throws exactly the same compilation error

error CS0311: The type 'AnonymousType#1' cannot be used as type parameter 'T' in the generic type or method 'System.Data.DataTableExtensions.CopyToDataTable<T>(System.Collections.Generic.IEnumerable<T>, System.Data.DataTable, System.Data.LoadOption)'. There is no implicit reference conversion from 'AnonymousType#1' to 'System.Data.DataRow'.

My code is :

DataTable tableSimCnfCopy = tableSimCnf.Clone ();

var varLst2 =

from car in tableSimCnf.AsEnumerable()

select new

{

ModelID = car.ModelID,

VehiclePrice = car.VehiclePrice,

APR24PercDown = car.APR24PercDown,

APR36PercDown = car.APR36PercDown,

APR48PercDown = car.APR48PercDown,

APR60PercDown = car.APR60PercDown,

APR72PercDown = car.APR72PercDown

};

varLst2.CopyToDataTable(tableSimCnfCopy, LoadOption.PreserveChanges);

The last line is the line I'm getting this compile error