This callback is used to validate cart line items before actions such as Save, Finalize, or Submit for Approval. In this example, the callback checks whether any line item has a quantity greater than 5.

using Conga.Revenue.Common.Callback;
using Conga.Revenue.Common.Callback.Models;
using Conga.Platform.Extensibility.CustomCode.Library;
using System.Collections.Generic;
using System.Threading.Tasks;
using Conga.Revenue.Common.Callback.Entities;
using Conga.Revenue.Common.Callback.Messages;

namespace CallbackProject {
  public class ValidationCallback : CodeExtensibility, IValidationCallback {
    
    public async Task BeforePricingValidationAsync(IActionRequest actionRequest) {
      await Task.CompletedTask;
    }

    // This method will trigger on Validate API call
    public async Task OnCartValidationAsync(IActionRequest actionRequest) {
      var cartContext = actionRequest.GetCartContext();
      var cartName = cartContext.GetCart().GetEntity().Name;

      // Trigger validation callback on Save action if QTY > 5
      if (cartName.Contains("ValidationCallback02")) {
        if (actionRequest.ActionName == "Save") {
          foreach (var lines in cartContext.GetLineItems()) {
            var chargelines = lines.GetChargeLines();
            foreach (var line in chargelines) {
              var li = line.GetEntity();
              if (li.Quantity > 5) {
                li.PricingStatus = "Error";
                var message = "Quantity is > 5 for LineItem " + li.Name;
                line.SetErrorDetails(message);
                lines.SetToRePricing();
              }
            }
          }
        }
      }

      // Trigger validation callback Warning on Save action if QTY > 5
      if (cartName.Contains("ValidationCallbackWarning01")) {
        if (actionRequest.ActionName == "Save") {
          foreach (var lines in cartContext.GetLineItems()) {
            var chargelines = lines.GetChargeLines();
            foreach (var line in chargelines) {
              var li = line.GetEntity();
              if (li.Quantity > 5) {
                var message = "Quantity is > 5 for LineItem " + li.Name;
                line.SetWarning(message);
                lines.SetToRePricing();
              }
            }
          }
        }
      }

      // Validation callback for Submit For Approval action if QTY > 5
      if (cartName.Contains("C0ValidationCallback")) {
        if (actionRequest.ActionName == "SubmitForApproval") {
          foreach (var lines in cartContext.GetLineItems()) {
            var chargelines = lines.GetChargeLines();
            foreach (var line in chargelines) {
              var li = line.GetEntity();
              if (li.Quantity > 5) {
                li.PricingStatus = "Error";
                var message = "Quantity is > 5 for LineItem " + li.Name;
                line.SetErrorDetails(message);
                lines.SetToRePricing();
              }
            }
          }
        }
      }
    }
  }
}

The process works as follows:

1. Start – The workflow is triggered when a cart action occurs (Save, Finalize, or Submit for Approval).

2. Validate Name and Action (Decision activity) – The workflow checks the cart name and action to determine which validation rule to apply. For example:

   • ValidationCallbackWarning01 → generates a warning.

   • ValidationCallback02 → shows an error on Save.

   • C0ValidationCallback → shows an error on Submit for Approval.

3. Check Quantity (Decision activity) – The workflow evaluates whether any line item quantity exceeds 5.

4. Error on Quantity (Error activity) – If the condition is true, the workflow raises an error message. Depending on the earlier decision branch, the action may be blocked or allowed with a warning.