Auto-Populate Item ID by Scanning Barcode in Dynamics 365 Finance & Operations (X++ Tutorial)

When working with Transfer Order / Sales Order / Purchase Order in Dynamics 365 F&O, the standard behavior requires the user to manually select the Item ID every time they add a new line.

But in many warehouses, users simply want to scan the barcode and automatically have the related item appear on the line — saving time and reducing manual errors.

Recently, I implemented this exact requirement:

When a user scans the item barcode on the Transfer Order line, the system should automatically fetch the Item ID linked with that barcode and populate the line.

To achieve this, I created a custom barcode field on the InventTransferLine table named MZNFRItemBarCode, and then added logic to validate the barcode and populate the ItemId automatically.

Below is the code I used.

X++ Code — Auto Populate Item ID By Scanning Barcode

[ExtensionOf(tableStr(InventTransferLine))]  
 final class MZNFRInventTransferLine_Extension  
 {  
   public boolean validateField(FieldId _fieldIdToCheck)  
   {  
     boolean ret = next validateField(_fieldIdToCheck);  
     switch (_fieldIdToCheck)  
     {  
       case(fieldNum(InventTransferLine, MZNFRItemBarCode)):  
       
         InventItemBarcode InventItemBarcode;  
         
         select * from InventItemBarcode  
         where InventItemBarcode.itemBarCode == this.MZNFRItemBarCode;  
         
         if(InventItemBarcode.itemId)  
         {  
           this.ItemId = InventItemBarcode.ItemId;
           //call ItemId modified method here to follow system behaviour.
         }  
         else  
         {  
           ret = checkFailed("ItemId not found with this barcode.");  
         }  
       break;  
     }  
     return ret;  
   }  
 }  

How This Code Works

1. 1. Custom Field for Barcode

   I added a custom field MZNFRItemBarCode to InventTransferLine.
   This is where the scanned barcode gets stored.

2. Overriding validateField

   The validateField() method is triggered when the user enters data in a field.
   So when the barcode field is filled (e.g., by a scanner), this method runs.

   3. Lookup in InventItemBarcode Table

   The code searches the InventItemBarcode table:

   • If the barcode exists → get the associated ItemId

   • If the barcode is invalid → show an error

3. Auto-Fill the Item ID

   When a valid barcode is found, the system automatically sets:

   this.ItemId = InventItemBarcode.ItemId;
   

   Thus, the transfer order line gets created without manual selection.

Result

✔ User scans the barcode
✔ Item ID automatically populates
✔ Faster data entry
✔ No manual item selection
✔ Reduced errors in warehouse operations