/// <summary>
/// Creates and returns a unit of work to the caller.
/// If a unit of work is already being used, throws an exception.
/// Allows only one instance of unit of work to exist.
/// </summary>
/// <returns></returns>
public virtual IUnitOfWork GetUnitOfWork()
{
if (_UnitOfWork != null)
throw new Exception("a unit of work is already in use.");
else
{
//If we are not responsible for keeping connection open,
//then create and return a unit of work
if (!KeepConnectionAlive)
{
_Context = new EFDbContext(DatabaseName);
if (_FirstRequest)
{
_Context.Database.Initialize(force: false);
_FirstRequest = false;
}
}
else
{
//We need to create a dbconnection and keep it running.
//Type of dbconnection depends on the db engine we are using
//SqlConnection for SqlServer, SqlCeConnection for CE
if (_DbConnection == null)
{
string connectionString = null;
if (DisableSqlCe)
{
//Using SqlServer
_DbConnection = new SqlConnection();
//localDb string
//connectionString = "Server=(localdb)\\v11.0;Integrated Security=true;";
//"Server=(localdb)\\Test;Integrated Security=true;AttachDbFileName= myDbFile;"
connectionString = @" Server=.\SQLEXPRESS; Database=" +
DatabaseName +
"; Trusted_Connection=true";
}
else
{
//Using SqlCe
_DbConnection = new SqlCeConnection();
connectionString = "Data Source=" + DatabaseName;
}
//Create a context and initialize the db on startup.
if (_FirstRequest)
{
using (var tempContext = new EFDbContext(connectionString))
{
tempContext.Database.Initialize(force: false);
}
_FirstRequest = false;
}
_DbConnection.ConnectionString = connectionString;
_DbConnection.Open();
}
_Context = new EFDbContext(_DbConnection, false);
}
_UnitOfWork = new UnitOfWork(_Context);
return _UnitOfWork;
}
}
/// <summary>
/// Closes a previously created unit of work and disposes the underlying resources.
/// If no context was created, throws an exception.
/// </summary>
public virtual void ReturnUnitOfWork()
{
if (_UnitOfWork != null)
{
//If we do not own the connection, it should be already closed/
if (!KeepConnectionAlive)
{
if (_DbConnection != null)
throw new Exception("Database connection is not null in disconnected state.");
}
else if (_DbConnection == null || _DbConnection.State != System.Data.ConnectionState.Open)
throw new Exception("Database connection is not open in connected state.");
//disposes dbcontext as well.
_UnitOfWork.Dispose();
_UnitOfWork = null;
_Context = null;
}
}
