Pass Data Between Plug-Ins

The message pipeline model defines a parameter collection of custom data values in the execution context that is passed through the pipeline and shared among registered plug-ins, even from different 3rd party developers. This collection of data can be used by different plug-ins to communicate information between plug-ins and enable chain processing where data processed by one plug-in can be processed by the next plug-in in the sequence and so on. This feature is especially useful in pricing engine scenarios where multiple pricing plug-ins pass data between one another to calculate the total price for a sales order or invoice. Another potential use for this feature is to communicate information between a plug-in registered for a pre-event and a plug-in registered for a post-event.
The name of the parameter that is used for passing information between plug-ins is SharedVariables. This is a collection of key\value pairs. At run time, plug-ins can add, read, or modify properties in the SharedVariables collection. This provides a method of information communication among plug-ins.
This sample shows how to use SharedVariables to pass data from a pre-event registered plug-in to a post-event registered plug-in.

               

using System;  // Microsoft Dynamics CRM namespace(s) using Microsoft.Xrm.Sdk;  namespace Microsoft.Crm.Sdk.Samples {     /// <summary>     /// A plug-in that sends data to another plug-in through the SharedVariables     /// property of IPluginExecutionContext.     /// </summary>     /// <remarks>Register the PreEventPlugin for a pre-event and the      /// PostEventPlugin plug-in on a post-event.     /// </remarks>     public class PreEventPlugin : IPlugin     {         public void Execute(IServiceProvider serviceProvider)         {             // Obtain the execution context from the service provider.             Microsoft.Xrm.Sdk.IPluginExecutionContext context = (Microsoft.Xrm.Sdk.IPluginExecutionContext)                 serviceProvider.GetService(typeof(Microsoft.Xrm.Sdk.IPluginExecutionContext));              // Create or retrieve some data that will be needed by the post event             // plug-in. You could run a query, create an entity, or perform a calculation.             //In this sample, the data to be passed to the post plug-in is             // represented by a GUID.             Guid contact = new Guid("{74882D5C-381A-4863-A5B9-B8604615C2D0}");              // Pass the data to the post event plug-in in an execution context shared             // variable named PrimaryContact.             context.SharedVariables.Add("PrimaryContact", (Object)contact.ToString());         }     }      public class PostEventPlugin : IPlugin     {         public void Execute(IServiceProvider serviceProvider)         {             // Obtain the execution context from the service provider.             Microsoft.Xrm.Sdk.IPluginExecutionContext context = (Microsoft.Xrm.Sdk.IPluginExecutionContext)                 serviceProvider.GetService(typeof(Microsoft.Xrm.Sdk.IPluginExecutionContext));              // Obtain the contact from the execution context shared variables.             if (context.SharedVariables.Contains("PrimaryContact"))             {                 Guid contact =                     new Guid((string)context.SharedVariables["PrimaryContact"]);                  // Do something with the contact.             }         }     } } 

It is important that any type of data added to the shared variables collection be serializable otherwise the server will not know how to serialize the data and plug-in execution will fail.
For a plug-in registered in stage 20 or 40, to access the shared variables from a stage 10 registered plug-in that executes on create, update, delete, or by a RetrieveExchangeRateRequest, you must access the ParentContext.SharedVariables collection. For all other cases, IPluginExecutionContext.SharedVariables contains the collection.