web.config connectionString

 <connectionStrings>
    <!-- add name="ConnectionString" connectionString="Password=[password];Persist Security Info=True;User ID=[id];Initial Catalog=[database name];Data Source=[local]" providerName="System.Data.SqlClient"/ -->
    <add name="ConnectionString" connectionString="Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|isBoard.mdf;Integrated Security=True;User Instance=True" providerName="System.Data.SqlClient"/>
  </connectionStrings>