Sql – a ListView, a LinqDataSource, linq-to-sql and ordering

asp.netlinqlinq-to-sql

So I'm writing a page which does some reporting and it's pretty dynamic, the user has the ability to group data and sort columns. I've been able to get my dynamic grouping down and then the sorting except now my generated linq-to-sql sql order by statement is backwards from what I want it to be. I think I need to figure out how to get at the Result returned from the LinqDataSource when the Sorting event is fired in the ListView so that I can then append my grouping order by clauses.

Currently I'm overriding the LinqDataSource selecting event to provide it's result and do the dynamic grouping there, but then the Result is modified by the Sort on the listview and I was thinking there must be some way to get at that result during the Sorting or Sorted event.

Any insight would be appreciated, in the meantime I will be attempting to figure this out myself.

Best Answer

Awesome I think I found my answer, set AutoSort to false on my LinqDataSource and then sort the data myself, since I'm already sorting myself for the other data.

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.net – Entity Framework vs LINQ to SQL

LINQ to SQL only supports 1 to 1 mapping of database tables, views, sprocs and functions available in Microsoft SQL Server. It's a great API to use for quick data access construction to relatively well designed SQL Server databases. LINQ2SQL was first released with C# 3.0 and .Net Framework 3.5.

LINQ to Entities (ADO.Net Entity Framework) is an ORM (Object Relational Mapper) API which allows for a broad definition of object domain models and their relationships to many different ADO.Net data providers. As such, you can mix and match a number of different database vendors, application servers or protocols to design an aggregated mash-up of objects which are constructed from a variety of tables, sources, services, etc. ADO.Net Framework was released with the .Net Framework 3.5 SP1.

This is a good introductory article on MSDN: Introducing LINQ to Relational Data

C# – LINQ query on a DataTable

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.

Below is query with Lambda Expression,

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

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Related Solutions

.net – Entity Framework vs LINQ to SQL

C# – LINQ query on a DataTable

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