Sample code for Plugin using Plugin Images in Dynamics 365 or Power Apps Dataverse

using Microsoft.Xrm.Sdk;
using Microsoft.Xrm.Sdk.Query;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace MetroBankProject
{
    public class restrictlessterm : IPlugin
    {
        public void Execute(IServiceProvider serviceProvider)
        {
            // Obtain the execution context from the service provider.  
            IPluginExecutionContext context = (IPluginExecutionContext)
                serviceProvider.GetService(typeof(IPluginExecutionContext));

            // Obtain the organization service reference which you will need for  
            // web service calls.  
            IOrganizationServiceFactory serviceFactory =
                (IOrganizationServiceFactory)serviceProvider.GetService(typeof(IOrganizationServiceFactory));
            IOrganizationService service = serviceFactory.CreateOrganizationService(context.UserId);


            // The InputParameters collection contains all the data passed in the message request.  
            if (context.InputParameters.Contains("Target") &&
                context.InputParameters["Target"] is Entity)
            {
                Entity entity = (Entity)context.InputParameters["Target"];

                if (entity.LogicalName.ToLower() == "hdfc_investment")
                {
                    //core logic 
                    Entity preentityImage = (Entity)context.PreEntityImages["myPreImage"];

                    var preTerm = preentityImage.Attributes["hdfc_totalterminmonths"];
                    var postTerm = entity.Attributes["hdfc_totalterminmonths"];

                    if (Convert.ToInt32(postTerm) > Convert.ToInt32(preTerm))
                    {
                        throw new InvalidPluginExecutionException("You cannot change term from lower to higher.");
                    }
                    else {
                        var fetchXML = @"<fetch version='1.0' output-format='xml-platform' mapping='logical' distinct='false'>
                                              <entity name='hdfc_emiinfo'>
                                                <attribute name='hdfc_emiinfoid' />
                                                <attribute name='hdfc_name' />
                                                <attribute name='createdon' />
                                                <order attribute='hdfc_name' descending='false' />
                                                <filter type='and'>
                                                  <condition attribute='hdfc_parentinvestment' operator='eq'  uitype='hdfc_investment' value='{0}' />
                                                </filter>
                                              </entity>
                                            </fetch>";
                        fetchXML = string.Format(fetchXML, entity.Id);

                        EntityCollection ec = service.RetrieveMultiple(new FetchExpression(fetchXML));
                        for (int i = 0; i < ec.Entities.Count; i++)
                        {
                            service.Delete("hdfc_emiinfo", ec.Entities[i].Id);
                        }


                        var amountofinvestment = ((Money)preentityImage.Attributes["hdfc_amount"]).Value;

                        //recreate new EMIs
                        for (int k = 0; k < Convert.ToInt32(postTerm); k++)
                        {
                            // create EMI Info
                            Entity entEMI = new Entity();
                            entEMI.LogicalName = "hdfc_emiinfo";
                            entEMI["hdfc_name"] = "Installmnt-" + (k + 1);
                            entEMI["hdfc_parentinvestment"] = new EntityReference(entity.LogicalName, entity.Id);
                            entEMI["hdfc_emiamount"] = new Money(amountofinvestment / Convert.ToInt32(postTerm));
                            entEMI["hdfc_emiduedate"] = DateTime.Now.AddMonths(k);
                            service.Create(entEMI);

                        }

                    }
                }
            }
        }
    }
}