private StockTicker(IHubConnectionContext <dynamic> clients)
{
Clients = clients;
var mapper = new ModelToTableMapper <Stock>();
mapper.AddMapping(s => s.Symbol, "Code");
_tableDependency = new SqlTableDependency <Stock>(
ConfigurationManager.ConnectionStrings["connectionString"].ConnectionString,
"Stocks", mapper.ToString());
_tableDependency.OnChanged += SqlTableDependency_Changed;
_tableDependency.OnError += SqlTableDependency_OnError;
_tableDependency.Start();
}