LINQ query on a DataTable

I'm trying to perform a LINQ query on a DataTable object and bizarrely I am finding that performing such queries on DataTables is not straightforward. For example:

var results = from myRow in myDataTable
where results.Field("RowNo") == 1
select results;

This is not allowed. How do I get something like this working?

I'm amazed that LINQ queries are not allowed on DataTables!

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You can't query against the DataTable 's Rows collection, since DataRowCollection doesn't implement IEnumerable<T> . You need to use the AsEnumerable() extension for DataTable . Like so:

var results = from myRow in myDataTable.AsEnumerable()
where myRow.Field<int>("RowNo") == 1
select myRow;

And as Keith says, you'll need to add a reference to System.Data.DataSetExtensions

AsEnumerable() returns IEnumerable<DataRow> . If you need to convert IEnumerable<DataRow> to a DataTable , use the CopyToDataTable() extension.

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var results = from DataRow myRow in myDataTable.Rows
    where (int)myRow["RowNo"] == 1
    select myRow

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It's not that they were deliberately not allowed on DataTables, it's just that DataTables pre-date the IQueryable and generic IEnumerable constructs on which Linq queries can be performed.

Both interfaces require some sort type-safety validation. DataTables are not strongly typed. This is the same reason why people can't query against an ArrayList, for example.

For Linq to work you need to map your results against type-safe objects and query against that instead.

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