What are Shared Variables and How to use them in Dynamics CRM Plugins?

Introduction: In Dynamics CRM, plugins play a crucial role in extending the platform's functionality and automating business processes. One of the key features that make plugins flexible and powerful is the use of shared variables. Shared variables allow data to be shared and passed between different stages of plugin execution, making it easier to manipulate and pass information as needed. In this blog post, we'll dive into the concept of shared variables, their significance, and provide a practical script to demonstrate their usage in Dynamics CRM plugins.

What are Shared Variables?

Shared variables, as the name suggests, are variables that can be shared and accessed across various stages of plugin execution. They allow developers to store and retrieve data at different points during plugin processing, ensuring seamless communication between pre-operation, post-operation, and any other custom stages. This flexibility is particularly useful when you need to maintain the state of an object, pass data between stages, or share data between different plugin classes.

The Usage of Shared Variables in Dynamics CRM Plugins:

Shared variables in Dynamics CRM plugins are achieved through the "PluginExecutionContext" object. This object contains a "SharedVariables" property, which is a dictionary-like collection of key-value pairs. Developers can use this property to store and retrieve data between different plugin stages.

The following steps outline how shared variables can be utilized in Dynamics CRM plugins:

Step 1: Create a new Plugin Project in Visual Studio and define the required steps and images.

Step 2: Register the plugin in the CRM environment, specifying the message, entity, and stages you want to target.

Step 3: Implement the plugin logic in the Execute method of your plugin class. Here's a sample code snippet to demonstrate the usage of shared variables:

using System;
using Microsoft.Xrm.Sdk;

namespace MyDynamicsPlugin
{
    public class MyPlugin : IPlugin
    {
        public void Execute(IServiceProvider serviceProvider)
        {
            // Obtain the execution context from the service provider.
            IPluginExecutionContext context = (IPluginExecutionContext)serviceProvider.GetService(typeof(IPluginExecutionContext));

            try
            {
                // Check if the plugin is being executed in the pre-operation stage for a specific message.
                if (context.Stage == 20 && context.MessageName.ToLower() == "create")
                {
                    // Get the target entity from the context.
                    Entity targetEntity = (Entity)context.InputParameters["Target"];

                    // Read data from the target entity.
                    string firstName = targetEntity.Contains("firstname") ? targetEntity["firstname"].ToString() : "";

                    // Store the data in a shared variable.
                    context.SharedVariables["FirstName"] = firstName;
                }

                // Check if the plugin is being executed in the post-operation stage for a specific message.
                if (context.Stage == 40 && context.MessageName.ToLower() == "create")
                {
                    // Retrieve data from the shared variable.
                    if (context.SharedVariables.Contains("FirstName"))
                    {
                        string firstName = context.SharedVariables["FirstName"].ToString();

                        // Perform additional logic with the retrieved data.
                        // ...

                        // Clear the shared variable if needed.
                        context.SharedVariables.Remove("FirstName");
                    }
                }
            }
            catch (Exception ex)
            {
                // Handle any exceptions that might occur during plugin execution.
                throw new InvalidPluginExecutionException("An error occurred: " + ex.Message);
            }
        }
    }
}

Conclusion:

Shared variables are a powerful tool in Dynamics CRM plugins that facilitate seamless communication and data sharing between different stages of plugin execution. By utilizing the "PluginExecutionContext" object, developers can store and retrieve data easily, making plugins more flexible and efficient. Incorporate shared variables into your plugin development, and you'll be able to implement sophisticated business processes and automation within your Dynamics CRM environment. Happy coding!