x++ validateWrite table method

X++ is the object-oriented language used by Dynamics 365 Finance & Operations (and older AX). It looks and feels a lot like C# with some SQL-ish extensions, and it runs on the application server to drive business logic, data access, and UI behaviors. A “table method” is simply a method that lives on a table object (for example, SalesLine.validateWrite()), so it runs whenever code works with rows of that table—no matter whether the change came from a form, a service, or a batch job. validateWrite() is one of those standard table methods: the platform calls it automatically right before a record is inserted or updated. If it returns false, the save is stopped; if it returns true, the write proceeds. You can extend this method to add your own business rules.

Now imagine a warehousing/retail/manufacturing electronics scenario: for any electronics item on a sales line, we want a serial number, a warranty code, and to block a direct ship path from the manufacturing site to a specific retail DC. We’ll use Chain of Command (CoC) to extend the SalesLine table’s validateWrite() without touching Microsoft’s base code.

// Extension of SalesLine.validateWrite using Chain of Command.
// Business rules for Electronics:
// 1) Require serial number on the line.
// 2) Require a warranty code (custom extension field).
// 3) Disallow direct shipments from MFG01 to RTLDIST.

[ExtensionOf(tableStr(SalesLine))]
final class SalesLine_ValidateWrite_ElectronicsCoC
{
    public boolean validateWrite()
    {
        boolean ok = next validateWrite(); // keep base validations (mandatory fields, etc.)
        if (!ok)
        {
            return false;
        }

        // Look up the item and dimensions relevant to this line
        InventTable it  = InventTable::find(this.ItemId);
        InventDim   dim = this.inventDim(); // current line’s site/warehouse/serial/etc.

        // Treat item group 'ELEC' as electronics
        if (it && it.ItemGroupId == 'ELEC')
        {
            // 1) Require serial number for electronics
            if (!dim.InventSerialId)
            {
                error("Electronics require a serial number on the sales line.");
                return false;
            }

            // 2) Require a warranty code (assumes you added an extension field on SalesLine)
            if (!this.aeWarrantyCode) // EDT/string field you added via an extension
            {
                error("Electronics require a warranty code.");
                return false;
            }

            // 3) Block direct route from manufacturing site to a specific retail DC
            if (dim.InventSiteId == 'MFG01' && dim.InventLocationId == 'RTLDIST')
            {
                error("Direct shipments from MFG01 to RTLDIST are not allowed. Use the designated cross-dock flow.");
                return false;
            }
        }

        return true; // all good—record can be written
    }
}

That’s along the lines of what you might need: a small, surgical CoC extension that keeps Microsoft’s base checks, then adds practical warehouse/retail/manufacturing rules for electronics.