x++ json serializer

If you’re looking for high quality version of  Microsoft’s MB-500 x++ language training or just starting with X++ Dynamics Edge is the right place going beyond Microsoft learn intended for self study, Dynamics Edge Instructor Led training is aimed at a faster, guided more in depth learning experience. one of the most practical skills you’ll need is working with JSON. Integrations, warehouse apps, and retail systems all speak JSON. In d365fo json serialization and deserialization, the go-to pattern is: mark your class with [DataContract], decorate each parm with [DataMember("JsonKey")], and then pass it to FormJsonSerializer. That’s the x++ json serializer in action. For arrays (like inbound lines in a shipment), you’ll use FormJsonSerializer::deserializeCollection(classNum(YourContract), json) to bind a JSON array into a List of objects.

Contracts Are Your Bridge to the Outside World

Think of contracts like translators: they map JSON keys into strongly typed fields. For example, an electronics manufacturer sending an advance ship notice (ASN) might define a contract WmsAsnDC for the header and another WmsAsnLineDC for its lines. Each property gets a [DataMember("...")]. When JSON like {"asnId":"ASN-1001","lines":[...]} arrives from a warehouse partner, your contracts give you strongly typed asnId and lines in X++. This avoids brittle string parsing and keeps your code upgrade-friendly.

One Serializer, Two Directions

The x++ jsonserializer isn’t just for reading data—it writes too. With FormJsonSerializer::serializeClass(myContract), you can take your ASN or shipment confirmation object and send it outbound to a partner system. For inbound flows, you flip it: FormJsonSerializer::deserializeObject(classNum(MyContract), json). If your payload starts with an array, you switch to deserializeCollection. These two methods cover 90% of what you’ll need, whether you’re building retail APIs or receiving warehouse updates.

A Warehouse Example in Practice

Here’s a trimmed-down version of the ASN header we looked at:

[DataContract]  
class WmsAsnDC  
{  
    str asnId;  

    [DataMember("asnId")]  
    public str parmAsnId(str v = asnId) { asnId = v; return v; }  
}  

// Deserialize inbound ASN JSON  
str json = '{"asnId":"ASN-240915-001"}';  
WmsAsnDC inbound = FormJsonSerializer::deserializeObject(classNum(WmsAsnDC), json);  
info(strFmt("ASN received: %1", inbound.parmAsnId()));  

Even with this minimal setup, you’ve bridged a real JSON message into X++ objects—exactly the kind of exercise you’d see in an MB-500 lab.

Pitfalls and How to Dodge Them

New to D365FO? These traps catch beginners often: forgetting [DataCollection] on lists (your array will come back empty), mismatching JSON key names (case and spelling count), or expecting JSON dates to “just work” (always send/receive them as ISO-8601 strings like 2025-09-27T14:00:00Z). If you keep those in mind, your d365fo json serialization and deserialization projects will run smoother, whether you’re coding for retail, manufacturing, or warehouse management.