Sample Plug-in: Compare Pre and Post images on Update

We often use Update message to execute something after identifying whether a particular value is changed from A to B. Typically, we might need to handle some logic to be run upon state change which is defined as a custom field (actually an optionsetvalue). In this case, we need to implement a post update plug-in with two images. Here images are snapshots of the entity in pre/ post execution which enables us to compare some values.

Scenario I am explaining got a custom field called new_officestatus which holds the status of office (new_office entity). It says whether a given office is a main, regional or sub office.

Suppose we need to do something when an office is converted from Sub to Regional.  What we going to do is compare the values of the status in each update action. Below are the optionsetvalues;

Regional - 100000001
Sub – 100000002
Main – 100000003

If we find Pre image with 100000002 and Post image with 100000001, it is the exact time that a sub office is converted to a regional one, which we need to execute our custom logic. Below code shows how it’s being done programmatically.

using System;
using System.Collections.Generic;
using Microsoft.Xrm.Sdk;
using Microsoft.Xrm.Sdk.Query;
using System.ServiceModel;

namespace TestCompany.CRM.Plugin
{
public class officeUpdate : IPlugin
 {
  public void Execute(IServiceProvider serviceProvider)
  {
   IPluginExecutionContext context;
   IOrganizationServiceFactory factory;
   IOrganizationService service;
   Entity PreImage;
   Entity PostImage;

   try
   {
     context = (IPluginExecutionContext)serviceProvider.GetService(typeof(IPluginExecutionContext));
     factory = (IOrganizationServiceFactory)serviceProvider.GetService(typeof(IOrganizationServiceFactory));
     service = factory.CreateOrganizationService(context.UserId);

     PreImage = (Entity)context.PreEntityImages["PreUpdateImage"];
     PostImage = (Entity)context.PostEntityImages["PostUpdateImage"];

     int _preOfficestatusVal = 0;
     int _postOfficestatusVal = 0;

     if (PreImage.Contains("new_officestatus"))
     { _preOfficestatusVal = ((OptionSetValue)PreImage["new_officestatus"]).Value; }
     if (PostImage.Contains("new_officestatus"))
     { _postOfficestatusVal = ((OptionSetValue)PostImage["new_officestatus"]).Value; }

     if ((_preOfficestatusVal == 100000002) && (_postOfficestatusVal == 100000001))
     {
        // Logic for - Sub converted to Regional
     }

    }
    catch (FaultException<OrganizationServiceFault> e)
    {
      throw e;
    }
    finally
    {
      service = null;
      factory = null;
      context = null;
      PreImage = null;
      PostImage = null;
    }
  }
 }
}

Now we will see plug-in registration. Here, we register two images for Pre and Post stages. They have the same name as images we read from the context in the code.

Related posts;

Plug-in concerns: synchronous or asynchronous, transactional or not …

Sample Plug-in: Delete
Sample Plug-in: State change
Sample Plug-in code: Create and Update
Retrieve attributes of entity object