Update same record based on multiple fields

This example is similar to the one above, but let’s assume our total is on same entity.

• In order to change the total on the fly, the plug-in needs to be pre-update
• This means we do not have access to post image, and have to use the pre-image instead. Therefore, we need to get all the changed values from the target, and unchanged values from the image.

Plug-in Code

if (context.InputParameters != null)
            {
                //Get Target - includes everything changed
                Entity entity = (Entity)context.InputParameters["Target"];

                //Get Pre Image
                Entity image = context.PreEntityImages["PreImage"];

                //If value was changed, get it from target.
                //Else, get the value from preImage
                Money rate = null;
                if(entity.Attributes.Contains("po_rate"))
                    rate = (Money)entity.Attributes["po_rate"];
                else
                    rate =  (Money)image.Attributes["po_rate"];
                int units = 0;
                if (entity.Attributes.Contains("po_units"))
                    units = (int)entity.Attributes["po_units"];
                else
                    units = (int)image.Attributes["po_units"];

                //Multiply
                Money total = new Money(rate.Value * units);

                //Set the value to target
                entity.Attributes.Add("po_total",total);

                //No need to issue additional update
            }

There is no need to use service.update here.