Nice examples of using .NET 4 dynamic keyword with Linq?

Question

So I Just got a recommendation from Amazon for LINQ to Objects Using C# 4.0: Using and Extending LINQ to Objects and Parallel LINQ (PLINQ).

It says that the book introdu

Answer 1

Joe's answer is cool. I have an idea how to simplify the usage. If you add this to the extension class:

public static class Extensions
{    

    public static IEnumerable ExecuteSql(this UserQuery uq, string sql)
    {
        var connStr="Provider=SQLOLEDB.1;"+uq.Connection.ConnectionString; 

        OleDbConnection connection = new OleDbConnection(connStr);
        DataSet myDataSet = new DataSet();
        connection.Open();

        OleDbDataAdapter DBAdapter = new OleDbDataAdapter();
        DBAdapter.SelectCommand = new OleDbCommand(sql, connection); 
        DBAdapter.Fill(myDataSet);

        var result = myDataSet.Tables[0].AsDynamic();
        return result;
    }
}

It allows to use queries like this in LINQPad:

void Main()
{
    var query1 = from cust in this.ExecuteSql("SELECT * from Customers")
        where cust.ContactName.StartsWith ("C")
        orderby cust.ContactName
        select new { cust.CustomerID, cust.ContactName, cust.City };        
    query1.Dump();      
}

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N.B.: You need to add the following references:

• Add System.Data.OleDb from the System.Data assembly to the query properties

• Add System.Dynamic to the query properties

• uq.Connection is only available if you have associated a database via the Connection dropdown. If you have selected "", a compile error will occur.

---

Update: I noticed that Joe has added a function ExecuteQueryDynamic in the latest Beta v4.53.03 of LinqPad, which can be used to achieve this, for example:

void Main()
{
    var q=this.ExecuteQueryDynamic("select * from Customers");
    q.Dump();
}

This will return the Customers table from the Northwind database as IEnumerable, using a Linq2Sql connection.