How to use Reflection with instance methods

If i create the following method concerning transaction :

public static int Insert(string processMethod, object[] processParameters, Type processType, object process, UserTransactionDTO transObj, string spPostConfirm, int toEmpNum,int confirmState)
        {
            int affectedRows = -7;
            using (IfxConnection conn = new IfxConnection(ConfigurationManager.ConnectionStrings["crms"].ToString() + " Enlist=true;"))
            {
                if (conn.State == ConnectionState.Closed)
                {
                    conn.Open();
                }
                using (IfxTransaction tran = conn.BeginTransaction())
                {

                    if (!string.IsNullOrEmpty(processMethod))//business Method
                    {
                        processParameters[1] = conn;
                        processParameters[2] = tran;
                        MethodInfo theMethod = processType.GetMethod(processMethod, new[] { processParameters.First().GetType(), typeof(IfxConnection), typeof(IfxTransaction) });
                        object res = theMethod.Invoke(process, processParameters);
                        transObj.ValuesKey = res.ToString();
                    }
                    if (!string.IsNullOrEmpty(transObj.ValuesKey))
                    {
                        affectedRows = RunPreConfirm(transObj.TaskCode, transObj.UserStateCode, transObj.ValuesKey, conn, tran, confirmState);//sp_confirm
                        if (affectedRows != 1)
                        {
                            tran.Rollback();
                            tran.Dispose();//Dispose
                            conn.Close();
                            conn.Dispose();
                            return -1;//Fail
                        }
                        affectedRows = InsertTrans(transObj, conn, tran);//MainTransaction --->df2usertrans

                        if (affectedRows == 1)//Success
                        {

                            if (!string.IsNullOrEmpty(spPostConfirm))
                            {
                                affectedRows = RunPostConfirm(spPostConfirm, transObj.ValuesKey, conn, tran);//sp_post_confirm
                                if (affectedRows != 0)
                                {
                                    tran.Rollback();
                                    tran.Dispose();//Dispose
                                    conn.Close();
                                    conn.Dispose();
                                    return -2;//Fail 
                                }

                            }

                            affectedRows = RunAfterTrans(transObj.TaskCode, transObj.OldStatusCode, transObj, toEmpNum, conn, tran);//sp_after_trans
                            if (affectedRows != 1)
                            {
                                tran.Rollback();
                                tran.Dispose();//Dispose
                                conn.Close();
                                conn.Dispose();
                                return -3;//Fail
                            }

                            tran.Commit();
                            tran.Dispose();
                            conn.Close();
                            conn.Dispose();
                            return 1;

                        }
                        else
                        {
                            tran.Rollback();
                            tran.Dispose();//Dispose
                            conn.Close();
                            conn.Dispose();
                            return -1;//Fail 
                        }
                    }
                    else
                    {
                        tran.Rollback();
                        tran.Dispose();//Dispose
                        conn.Close();
                        conn.Dispose();
                        return -1;//Fail 
                    }
                }
            }
            return affectedRows;
        }

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I want to ask three questions :

1-if one of my internal methods failed to insert before } Does the connection and the transaction disposed and closed automatically or not ?I mean should i call the following block of code :

tran.Dispose();
conn.Close();
conn.Dispose();

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2-Could i invoke an instance method with its properties instead of fill the object and passing it as a parameter again ?

 object res = theMethod.Invoke(process, processParameters);

I mean : I want to use this(with its object state) because it's instance method:

 public string InsertRequest(IfxConnection conn,IfxTransaction trans)

instead of this current method :

 public string InsertRequest(EnhancementRequest obj, IfxConnection conn,IfxTransaction trans)

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3-Is the following code written well? I mean, no redundant steps and no logical errors.?