Dynamics CE: Retrieve record based on account Id and find the GUID from entity reference

 The following code can be used to retrieve the record and find the GUID of the lookup field.

using System;

using System.ServiceModel;

using Microsoft.Xrm.Sdk;

using Microsoft.Xrm.Sdk.Messages;

using Microsoft.Xrm.Sdk.Query;

namespace XMA_UpdateOppotunityAccOwner.XMA_UpdateOpportunityAccOwner

{

  

    public class PostOperationaccountUpdate: IPlugin

    {

        public void Execute(IServiceProvider serviceProvider)

        {

            //Initializing Service Context.

            IPluginExecutionContext context = (IPluginExecutionContext)serviceProvider.GetService(typeof(IPluginExecutionContext));

            IOrganizationServiceFactory factory = (IOrganizationServiceFactory)serviceProvider.GetService(typeof(IOrganizationServiceFactory));

            IOrganizationService service = factory.CreateOrganizationService(context.UserId);

            try

            {

                //Defining Entity Object.

                Entity eTarget = null;

                if (context.MessageName == "Update")

                {

                    eTarget = (context.InputParameters.Contains("Target") && context.InputParameters["Target"] != null) ?

                    context.InputParameters["Target"] as Entity : null;

                    Guid accountIdGuid = eTarget.GetAttributeValue<Guid>("accountid");

                    RetrieveRequest request = new RetrieveRequest()

                    {

                        ColumnSet = new ColumnSet("ownerid"),

                        Target = new EntityReference("account", accountIdGuid)

                    };

                    var response = (RetrieveResponse)service.Execute(request);

                    Entity entity = response.Entity;

               Guid ownerId = ((EntityReference)entity.Attributes["ownerid"]).Id;//Find Guid from a lookup

                    RetrieveRequest requestUer = new RetrieveRequest()

                    {

                        ColumnSet = new ColumnSet("fullname"),

                        Target = new EntityReference("systemuser", ownerId)

                    };

                    response = (RetrieveResponse)service.Execute(requestUer);

                    entity = response.Entity;

                    var ownerName = entity["fullname"];

                    QueryExpression query = new QueryExpression();

                    query.EntityName = "opportunity";

                    query.ColumnSet = new ColumnSet("opportunityid", "parentaccountid", "name");

                    FilterExpression filter = new FilterExpression(LogicalOperator.And);

                    filter.AddCondition("parentaccountid", ConditionOperator.Equal, accountIdGuid);

                    query.Criteria.AddFilter(filter);

                    EntityCollection entityCollection = service.RetrieveMultiple(query);

                    if (entityCollection.Entities.Count > 0)

                    {

                        int TotalAccountCount = entityCollection.Entities.Count;

                        foreach (var accountEntity in entityCollection.Entities)

                        {

                            //Stage 6.

                            Entity opportunity = new Entity("opportunity");

                            opportunity.Id = accountEntity.Id;

                            opportunity["fieldName"] = ownerName;

                            service.Update(opportunity);

                        }

                    }

                }

            }

            catch (Exception ex)

            {

                throw new InvalidPluginExecutionException(ex.Message);

            }

        }

    }

}

Regards,

Arun S Keerthi