Пример асинхронного запроса
SqlConnection cn = new SqlConnection
  ("SERVER=sql2005;INTEGRATED SECURITY=True;"
    + "DATABASE=AdventureWorks;async=True");
SqlCommand cmd = new SqlCommand("SELECT * FROM Person.Contact", cn);
cmd.CommandType = CommandType.Text;
try
{
    cn.Open();
    IAsyncResult myResult = cmd.BeginExecuteReader();
    while (!myResult.IsCompleted)
    {
      // Perform other code actions
    }
    // Process the contents of the reader
    SqlDataReader rdr = cmd.EndExecuteReader(myResult);

    // Close the reader
    rdr.Close();
}
catch (Exception ex)
{
    MessageBox.Show(ex.Message);
}
finally
{
    cn.Close();
}

Поделитесь материалом с коллегами и друзьями