How to handle connections to use in Dapper?

Question

I am trying to use Dapper on a service layer. How should it handle the IDbConnection?

I am using this in a MVC5 project with StructureMap for IoC.

Can I inject it in the server layer classes? Or maybe a DapperWrapper as follows:

public class DapperWrapper {

  private ConnectionString { get { return Settings.ConnectionString; } }

  public IEnumerable<T> Query<T>(String sql, dynamic parameters = null) {

    IEnumerable<T> result;

    using (IDbConnection connection = new SqlConnection(_connection)) {
      connection.Open();
      result = SqlMapper.Query<T>(connection, sql, parameters);        
    }

    return result;

  } // Query

  // OTHER DAPPER METHODS
 }

I am afraid this approach opens and closes many connections. Is this a problem?
Should I inject a connection in the DapperWrapper, and if so, How?

What is the best way to do this?

There are some decent solutions at http://stackoverflow.com/questions/9218847/how-do-i-handle-database-connections-with-dapper-in-net — UtopiaLtd, Sep 18 '14 at 22:15

score 2 · Answer 1 · answered Sep 18 '14 at 22:41

As long as connection pooling is enabled (for SQL server it is enabled by default) you aren't actually opening and closing connections - you are fetching from / releasing to the connection pool. It should take microseconds only.
That is entirely a design decision. Injection works. On-demand construction works. In the case of an http request, you can also often make use of on-demand (deferred but cached) request-focused connection storage (just make sure you dispose it at the end of the request!).

How to handle connections to use in Dapper?

1 Answers1