Create Purchase Order,Confirm,Packing slip,Invoice in Ax 2012 through x++

static void createPO(Args _args)
{
    NumberSeq       numberSeq;
    Purchtable      Purchtable;
    PurchLine       PurchLine;
    PurchFormLetter purchFormLetter;

    ;
    ttsbegin;
    numberSeq =NumberSeq::newGetNum(purchparameters::numRefPurchId(),true);

    // Initialize Purchase order values
    Purchtable.initValue();
    Purchtable.PurchId = numberSeq.num();
    Purchtable.OrderAccount = 'US-101';
    Purchtable.CurrencyCode = 'USD';
    Purchtable.initFromVendTable();
    if (!Purchtable.validateWrite())
    {
        throw Exception::Error;
    }
    Purchtable.insert();

    // Initialize Purchase Line items
    PurchLine.PurchId = Purchtable.PurchId;
    PurchLine.ItemId = 'C0001';
    PurchLine.PurchQty = 2;
    PurchLine.createLine(true, true, true, true, true, false);
    PurchLine.clear();


    PurchLine.PurchId = Purchtable.PurchId;
    PurchLine.ItemId = 'C0002';
    PurchLine.PurchQty = 1;
    PurchLine.createLine(true, true, true, true, true, false);
    ttscommit;

        ////PO confirmation
    ttsBegin;
    purchTable = PurchTable::find(purchTable.PurchId);
    purchFormLetter = PurchFormLetter::construct(DocumentStatus::PurchaseOrder);
    purchFormLetter.update(purchTable, strFmt("Inv_%1", purchTable.PurchId));
    ttsCommit;

        //PO Product Receipt
    ttsBegin;
    purchFormLetter = purchFormLetter::construct(DocumentStatus::PackingSlip);
    purchFormLetter.update(purchtable, // Purchase record Buffer
    "PO_"+purchTable.PurchId, // Invoice Number
    systemdateget()); // Transaction date
    ttsCommit;
   

    //PO Invoice
    ttsBegin;
    purchFormLetter = purchFormLetter::construct(DocumentStatus::Invoice);
    //purchFormLetter.update(purchtable,"Inv_123",systemdateget()); // Transaction date
    //purchFormLetter.update(purchTable, strFmt("PO_%1", purchTable.PurchId));
    purchFormLetter.update(purchtable, // Purchase record Buffer
    "INV-"+purchTable.PurchId, // Invoice Number
    systemdateget()); // Transaction date
   
    ttscommit;
    if (PurchTable::find(purchTable.PurchId).DocumentStatus == DocumentStatus::Invoice)
    {
        info(strfmt("Posted invoiced journal for purchase order %1",purchTable.PurchId));
    }

}