Question

Here is the code I made, it usually works, but sometimes fails (1 out of 4 times more or less):

...
List<string> _items = new List<string>(); 
...
using (SqlCeConnection con = new SqlCeConnection(Globals.conString))
{
    string codbultocomp = null;
    con.Open();
    using (SqlCeCommand cmd = new SqlCeCommand("SELECT codbultocomp FROM envios WHERE codigodestino=@codigodestino AND estado=@pendiente", con))
    {
        cmd.Parameters.AddWithValue("@codigodestino", codigoDestino);
        cmd.Parameters.AddWithValue("@pendiente", "pendiente");

        SqlCeDataReader reader = cmd.ExecuteReader();

        while (reader.Read())
        {
            codbultocomp = reader["codbultocomp"].ToString();
            _items.Add(codbultocomp);
        }
        reader.Close();
    }
    listBox1.DataSource = _items;
} 

When it fails the application freezes, and if I pause the debug it is stopped in the last brace. I tried to show an error using a try/catch block but it didn’t show anything and stopped in the same place. I also tried to watch the listbox datasource shows this error in the “watch” list:

Unable to evaluate expression because the code is optimized or a native frame is on top of the call stack.

Any idea of what I’m doing wrong?

Answer 1

Call it after your using, all IDisposable objects will be disposed after using.

...
List<string> _items = new List<string>(); 
...
using (SqlCeConnection con = new SqlCeConnection(Globals.conString))
{
     ...
} 

listBox1.DataSource = _items;