How Can I Effectively Query DataTables Using LINQ in .NET?

Use Linq to query datatables: Full Guide

Although DataTables in .NET is easy to use and popular, executing the Linq query on it may encounter unexpected challenges. This article will explore these restrictions and provide gradual guidelines to help you successfully use Linq to query DataTables.

The reason for the failure of linq query on datatables directly

In contrast to the expected, LINQ query is not allowed directly to the datatable ROWS collection. This is because the DataRowCollection does not implement the Ienumerable interface. Therefore, the following code will fail:

Solution: Use asenumerable () expansion method

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

In order to solve this problem, you need to use the asenumerable () extension method provided in the name space provided in the name space of System.data.datasetexSIONSIONS. This expansion method converts Datatable to Ienumeration to allow Linq to query.

Lambda expression alternative scheme

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

You can also use Lambda expression to simplify the query:

<结果> Convert the result to datatable (optional)

If you need, you can use Copytodatatable () Expansion method to convert Ienumeration

var result = myDataTable
    .AsEnumerable()
    .Where(myRow => myRow.Field<int>("RowNo") == 1);

result back to DataTable:

<注意> Other precautions

Remember to add System.data.datasetextExEnsions to your project reference. In addition, please note that asenumerable () returns Ienumeration

instead of Ienumeration

var dataTableResult = result.CopyToDataTable();

, which may affect your subsequent operations.

By following these guidelines, you can effectively perform linq queries on DataTables to release the powerful features of Linq in data operation and analysis tasks.

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