executionContext.getEventArgs().preventDefault() not stopping BPF

Question

I have a Model Driven app with business process flow that I am trying to prevent the users from progressing if there is not records in a subgrid. I can get a dialog to pop, but the bpf advances to the next stage even when preventDefault is invoked.

formContext.data.process.addOnPreStageChange (Sdk.validateApprovers);

      this.validateApprovers = async function (executionContext) {
        let formContext = executionContext.getFormContext();
        let activeStage = formContext.data.process.getActiveStage().getName();
        let terminationId = formContext.data.entity.getId().replace(/[{}]/g, '');
        formContext.ui.clearFormNotification("ApproverError");
        formContext.ui.clearFormNotification("RecipientError");

        if (activeStage = 'Configuration') {
            let approverOptions = `?$select=new_approverid&$filter=statecode eq 0 and _new_relatedrecordid_value eq  ${terminationId}`;
            let recipientOptions = `?$select=new_recipientid&$filter=statecode eq 0 and _new_relatedrecord_value eq  ${terminationId}`;
            //isApproverRows = false;
            //isRecipientRows = false;
            
            await Xrm.WebApi.retrieveMultipleRecords("new_recipient", recipientOptions).then(
                function success(result) {
                    for (var i = 0; i < result.entities.length; i++) {
                        console.log(result.entities[i]);
                    }
                    if (result.entities.length === 0) {
                        let alertStrings = {
                            confirmButtonLabel: "OK",
                            text: "Recipients are not defined. Please specify.",
                            title: "Warning"
                        };
                        executionContext.getEventArgs().preventDefault();
                        Xrm.Navigation.openAlertDialog(alertStrings);
                    }
                },
                function (error) {
                    console.log(error.message);
                }
            );
        }
    }

Answer 1

I believe the reason is that you have an async call and preventDefault happens in the callback when the save happened already. I believe you will have to use an approach similar to the one I used before but for a pure save event - https://butenko.pro/2018/11/15/cancelling-save-based-on-the-result-of-async-operation/ Personally, I have never worked with addOnPreStageChange handler so I have no idea if would it work or not.

In the worst case scenario you can create a real-time workflow/plugin that will do checks and raise an error to prevent the save.