Hello'
I have successfully run the onLoad webresource in Case form to get Subject entity's GUID through lookup field---subjectid. Now Subject entity is replaced by a custom entiy, named Category, my purperse is get the Category entity's GUID throught run a webresource when loading Case record. The code as below:
function getCategoryLookupId(executionContext) {
debugger;
var formContext = executionContext.getFormContext();
var lookupObjValue = formContext.getAttribute("abc_opscategory").getValue();
if (lookupObjValue != null) {
var categoryId = lookupObjValue[0].id;
if (categoryId != null) {
Xrm.Utility.alertDialog("Category ID: " + categoryId);
}
}
}
When loading Case form, I have encounter an issue, lookupObjValue always is null. the screen as below

Appreciated for your help!