Question

My code :

var db = Database.Open("dbase");
var result = db.Query("SELECT event_id, description, title, event_start, event_end 
                       FROM event 
                       WHERE event_start >= "+ start + " AND event_end <= "+ @end);

foreach(var record in result)
{
   CalendarEvent cevent = new CalendarEvent();
   cevent.id = result.event_id; //error is thrown here
}

Error message :

CS1061: ‘System.Collections.Generic.IEnumerable’ does not
contain a definition for ‘event_id’ and no extension method ‘event_id’
accepting a first argument of type
‘System.Collections.Generic.IEnumerable’ could be found (are
you missing a using directive or an assembly reference?)

In my code I have :

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data;
using System.Data.SqlClient;
using WebMatrix.Data;

What is causing this?

Answer 1

Well to start with, you probably meant record.event_id instead of result.event_id. Your code would be clearer if you changed result to results, given that it’s the sequence of results.

However, that’s just going to move the problem on one stage. Database.Query returns an IEnumerable<object>, so the type of record is going to be object… and object doesn’t have a member called event_id either.

The documentation for Database.Query is pretty vague – it’s possible that it’s returning dynamic objects though. Try this:

foreach (dynamic record in result)
{
        CalendarEvent cevent = new CalendarEvent();
        cevent.id = record.event_id;
}

EDIT: If record.event_id is working even without converting to dynamic, then it’s possible that the effective result type is IEnumerable<dynamic> and MSDN is just not being terribly helpful.

However, there’s still a problem in your code: it’s a bad idea to include your parameter values directly in your SQL like that:

• Mixing code and data is a bad idea in terms of code cleanliness
• You need to make sure that dates, numbers etc are in the right format
• It opens you up to SQL injection attacks

Instead, you should use a parameterized query like this:

var result = db.Query(
     "SELECT event_id, description, title, event_start, event_end FROM event " +
     "where event_start >= ? AND event_end <= ?",
     start, end);