If I had the code below what are the best practise / design considersations for replacing it with IoC (we are looking to use Castle Windsor). As the "using" statement is responsible for creating the connection object, you can't inject that directly into the constructor or the method. Note: Using SQL connection as what appears to be a clean example, the main benefit here is mocking/unit testing
public void CustomerRespository
{
....
public void Save(Customer customer)
{
using (var cn = new SqlConnection(connectionString))
{
using (var cm = new SqlCommand(commandString, cn))
{
....
cn.Open();
cm.ExecuteNonQuery();
}
}
}
}
I believe there would be at least a few options, but as we're just starting out with IoC I'm not confident that they wouldn't cause us problems later on and/or fly in the face of IoC concepts. My favoured approach would be too modify the approach as follows, can anyone highlight potential issues with it?
public interface IDatabase
{
IDbConnection Connection(string connectionString);
IDbCommand Command(string text, IDbConnection conn);
}
public class SqlDB : IDatabase
{
IDbConnection Connection(string connectionString)
{ return new SqlConnection(connectionString); }
IDbCommand Command(string text, IDbConnection conn)
{ return new SqlCommand(text, conn); }
}
public interface ICustomerRespository
{
void Save(Customer customer)
}
public class CustomerRespository : ICustomerRespository
{
public IDatabase DB{get; private set;}
public CustomerRespository( IDatabase db)
{
DB = db;
}
....
public void Save(Customer customer)
{
using (var cn = DB.Connection(connectionString))
{
using (var cm = DB.Command(commandString, cn))
{
....
cn.Open();
cm.ExecuteNonQuery();
}
}
}
}