LINQ to dataset

[philip.joebstl]

Hi there,

I am working on a TxA- and -B- Series Target programming an application with database connection. So i thought about using a dataset and the "LINQ to Dataset" functionality. So I wrote the following code:

DataSet ds;
...
var result = ds.Tables["tabRecipe"].AsEnumerable()
.Where(row => row.IDRecipe == iIDRecipe && row.Priority >= iStepPriority)
.OrderBy(row => row.Priority)
.FirstOrDefault();
...

But when I'm trying to compile, the following error comes on:
"System.Data.DataTable" has no definition for "AsEnumerable", and there was no extension method "AsEnumerable...

The Microsoft .net documentation about LINQ in the .net cf says that LINQ to Dataset is also working on cf, and also the "AsEnumerable"-Method should be (like you can see here: http://msdn.microsoft.com/de-de/library ... 90%29.aspx)

So why does this piece of code not compile?

Thanks for the help!

[mark.monroe]

Only some of the methods are supported in CF and the AsEnumerable is not supported.

http://msdn.microsoft.com/en-us/library ... s.90).aspx

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[philip.joebstl]

Hi Mark,

I somehow didn't notice that these extension methods are not supported in CF.
As always, thank you for the quick answer!

[Patrick Hall]

According to Microsoft "Version Information" Section they are supported in Compact Framework 3.5, but you must add a reference in your build process to the System.Data.DataSetExtensions.dll. This isn't included in iX Developer projects by default... Have you tried adding the Assembly Reference Manually? You should still only add the single using in your script though...

Code: Select all

using System.Data;

Referenced Assembly Ribbon

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Then Browse for the Assembly in the Compact Framework SDK Folder.

Assembly Reference Browser

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Referenced Assemblies

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System.Data will then reference the System.Data.DataSetExtensions.dll and should allow access to the AsEnumerable() member.

When I do this I can build successfully without error, but... I can't confirm it will work on a T7A and T7B (because I have not downloaded it to a real device, only checked that it will build), though you should be able to test that by downloading your resulting project.