How to Update Activity Entity Record When Completed/Canceled Using CRM SDK C#

As we know, in the activity entity, after you completed or close/canceled an activity record, you cannot modify any value of this activity record. Well, it happened to any entity and you might need to re-open it first. But, sometimes, you need to update some fields when you cancel or complete activities, such as you want to give additional description, you want to save field based on the regarding field, or you want to add some calculation inside when you close any activities.

So, here we are, this is the code to update field when you close the activity, you need a plugin.

public void Execute(IServiceProvider serviceProvider)
        {
            #region must to have

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

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

            // Create service with context of current user
            IOrganizationService service = serviceFactory.CreateOrganizationService(context.UserId);

            //create tracing service
            ITracingService tracingService = (ITracingService)serviceProvider.GetService(typeof(ITracingService));

            #endregion

            string strStatus = string.Empty;

            if (context.InputParameters.Contains("Target") && context.InputParameters["Target"] is Entity)
            {

                //create entity context
                Entity entity = (Entity)context.InputParameters["Target"];

                if (entity.LogicalName != TFP.Xrm.Contoso.Task.EntityLogicalName)

                    return;

                try
                {
                    if (entity.Contains("statecode"))
                    {
                        //Update the description
                        strStatus = GetStateCodeText(service, entity.LogicalName, "statecode", 
                            ((OptionSetValue)entity["statecode"]).Value);
                        
                        //update the description field
                        entity["description"] = String.Format("{0} on {1}", strStatus, DateTime.Now.ToString("dd/MM/yyyy"));
                    }
                }
                catch (Exception ex)
                {
                    throw new InvalidPluginExecutionException(ex.Message);

                }

            }
        }

The most notable is this line:

if (entity.Contains("statecode"))
{


}

You can have your own logic, in my scenario is I want to update the description field in Task entity to capture the status (in text) + the time, I am sure that you guys have your own scenario , for example update another field based on the status and so one.

And the most important thing is you need to register this plugin onPreUpdate

Result:

See the updated Description field below.

Hope this helps!

Thanks.