LINQ to DataSet, DataTable.AsEnumerable() not recognized

GSTD picture GSTD · Oct 16, 2010 · Viewed 59.7k times · Source

I am brand new to LINQ and am trying to query my DataSet with it. So I followed this example to the letter, and it does not work.

I know that my DataTable needs the .AsEnumerable on the end, but it is not recognized by the IDE. What am I doing wrong? Am I missing a reference/import that is not shown in the example (wouldn't be the first time a MSDN example was not quite right), and if so, which one? Or is it something else altogether?

Sample Code:

Imports System
Imports System.Linq
Imports System.Linq.Expressions
Imports System.Collections.Generic
Imports System.Data
Imports System.Data.SqlClient
Imports System.Data.Common
Imports System.Globalization


//Fill the DataSet.
Dim ds As New DataSet()
ds.Locale = CultureInfo.InvariantCulture
//See the FillDataSet method in the Loading Data Into a DataSet topic.
FillDataSet(ds)

Dim products As DataTable = ds.Tables("Product")

Dim query = From product In products.AsEnumerable() _
            Select product
Console.WriteLine("Product Names:")
For Each p In query
    Console.WriteLine(p.Field(Of String)("Name"))
Next

The References in my project are:

System
System.Data
System.Drawing
System.Windows.Forms
System.Xml

Answer

tvanfosson picture tvanfosson · Oct 16, 2010

While the class holding the extensions is in the System.Data namespace, it's located in an assembly that isn't added to your project by default. Add a reference to System.Data.DataSetExtensions to your project and it should be ok. Remember that, even after you've added the reference, any class that expects to use the extension methods defined in the class will need to have a using statement for System.Data as well.