自定义代码活动无法在Dynamics CRM中为订单创建关注

Question

I am begginer to the Custom Code activity and I tried to create a an auto follow for a specific order when a subgrid on order form is updated. But, I am facing following exception in custom code activity to create a follow for an order in dynamics crm 2016. Your thoughts on it, how can I resolve it?

Source code

[RequiredArgument]
        [Input("InputEntity")]
        [ReferenceTarget("salesorder")]
        public InArgument<EntityReference> inputEntity { get; set; }

        [Output("createFollowPost")]
        [ReferenceTarget("postfollow")]
        public OutArgument<EntityReference> outputEntity { get; set; }

private void createFollow(IOrganizationService service, Guid ownerId, Guid orderId,CodeActivityContext caContext) {
            Entity postfollow = new Entity("postfollow");
            postfollow["ownerid"] = new EntityReference("systemuser",ownerId);
            postfollow["regardingobjectid"] = new EntityReference("salesorder",orderId);

            Guid followId = service.Create(postfollow);
            this.outputEntity.Set(caContext, inputEntity.Get(caContext));
            //this.outputEntity.Set(caContext, new EntityReference("postfollow", followId));
        }

Exception

Unhandled Exception: System.ServiceModel.FaultException`1[[Microsoft.Xrm.Sdk.OrganizationServiceFault, Microsoft.Xrm.Sdk, Version=8.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]]: Entity Reference cannot have Id and Key Attributes empty.Detail: 
<OrganizationServiceFault xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.microsoft.com/xrm/2011/Contracts">
  <ErrorCode>-2147220989</ErrorCode>
  <ErrorDetails xmlns:d2p1="http://schemas.datacontract.org/2004/07/System.Collections.Generic" />
  <Message>Entity Reference cannot have Id and Key Attributes empty.</Message>
  <Timestamp>2017-03-15T13:17:20.826911Z</Timestamp>
  <InnerFault>
    <ErrorCode>-2147220970</ErrorCode>
    <ErrorDetails xmlns:d3p1="http://schemas.datacontract.org/2004/07/System.Collections.Generic" />
    <Message>System.ArgumentException: Entity Reference cannot have Id and Key Attributes empty.</Message>
    <Timestamp>2017-03-15T13:17:20.826911Z</Timestamp>
    <InnerFault i:nil="true" />
    <TraceText i:nil="true" />
  </InnerFault>
  <TraceText>[Microsoft.Xrm.Sdk.Workflow: Microsoft.Xrm.Sdk.Workflow.Activities.RetrieveEntity]
[RetrieveEntity]
</TraceText>
</OrganizationServiceFault>
   at Microsoft.Crm.Extensibility.OrganizationSdkServiceInternal.Retrieve(EntityReference entityReference, ColumnSet columnSet, CorrelationToken correlationToken, CallerOriginToken callerOriginToken, WebServiceType serviceType, Boolean checkAdminMode)
   at Microsoft.Crm.Extensibility.InprocessServiceProxy.RetrieveCore(String entityName, Guid id, ColumnSet columnSet)
   at Microsoft.Xrm.Sdk.Client.OrganizationServiceProxy.Retrieve(String entityName, Guid id, ColumnSet columnSet)
   at Microsoft.Crm.Workflow.Services.RetrieveActivityService.<>c__DisplayClass1.<RetrieveInternal>b__0(IOrganizationService sdkService)
   at Microsoft.Crm.Workflow.Services.ActivityServiceBase.ExecuteInTransactedContext(ActivityDelegate activityDelegate)
   at Microsoft.Crm.Workflow.Services.RetrieveActivityService.ExecuteInternal(ActivityContext executionContext, RetrieveEntity retrieveEntity)
   at Microsoft.Crm.Workflow.Services.RetrieveActivityService.Execute(ActivityContext executionContext, RetrieveEntity retrieveEntity)
   at System.Activities.CodeActivity.InternalExecute(ActivityInstance instance, ActivityExecutor executor, BookmarkManager bookmarkManager)
   at System.Activities.Runtime.ActivityExecutor.ExecuteActivityWorkItem.ExecuteBody(ActivityExecutor executor, BookmarkManager bookmarkManager, Location resultLocation)

Answer 1

You may not be able to assign an owner as an attribute on create as you are doing here:

postfollow["ownerid"] = new EntityReference("systemuser",ownerId);

Instead, try to execute an AssignRequest after your Create() :

AssignRequest assign = new AssignRequest 
{
    Assignee = new EntityReference("systemuser", ownerId),
    Target = new EntityReference("postfollow", followId)
};

service.Execute(assign);

---

Also try checking that ownerId and orderId are valid:

if (orderId != null && orderId != Guid.Empty) { }

Answer 2

I think that you should change this line:

this.outputEntity.Set(caContext, inputEntity.Get(caContext));

your input entity is salesOrder and you are assigning this entity to outputEntity which is postFollow. The line you commented out looks much better:

this.outputEntity.Set(caContext, new EntityReference("postfollow", followId));

but the even better looking code would be:

postFollow.Id = service.Create(postfollow);

this.outputEntity.Set(caContext, postFollow.ToEntityReference());

Also make sure that both ownerId and orderId that are passed to your function have valid ids and LogicalNames for existing records in your system.