Use of Shared Variables in Dynamics CRM 2011 Plugins

Introduction of Shared Variables in MS CRM2011 Plug-in might not been used by most of us, as we are not aware of its unique feature. This Shared Variables will be useful for sharing the data during complex plug-in development by sharing the data between plug-ins registered on both the pre and post events.

Any values can be stored in the plugin context of Pre-event will be available in the Post-event of the plugin. This way we can avoid storing the values in a custom attribute. Certain data validation which needs to be done at post-event can be achieved by passing the value from pre-event of the plugin. This also helps for performing business logics like updating related records asynchronously.

The below code snippet illustrates the usage of Shared Variable.  This sample explains the data validation done at post-event operation based on the value received from the pre-event operation where a flag is updated with a value at the pre-event level and sent to the post-event through shared variable.

Pre-Create (Entity Name) Plug-in

if (pluginContext.MessageName == "Create")

                        {

                            if (pluginContext.InputParameters.ContainsKey("Target") && pluginContext.InputParameters["Target"] is Entity)

                            {

                                Entity targetEntity = context.InputParameters["Target"] as Entity;

                                if (targetEntity != null)

                                {

                                    bool setFlag = false;

                                    //Check data validation for attributes                                  

                                    string country = targetEntity.Attributes["address1_country"];

                                    OptionSetValue industryCode = (OptionSetValue)target.Attributes["industrycode"];

                                   

                                    // Country is US and Industry Type is Accounting are Preferred 

                                    if (country.ToLower() == "us" && industryCode.Value == 1)

                                    {

                                        setFlag = true;

                                    }                                   

                                    pluginContext.SharedVariables.Add("flag", setFlag);

                                }

                            }

                        }

Post-Create (Entity Name) Plug-in

if (pluginContext.MessageName == "Create")

                        {

                            if (pluginContext.InputParameters.ContainsKey("Target") && pluginContext.InputParameters["Target"] is Entity)

                            {

                                Entity targetEntity = pluginContext.InputParameters["Target"] as Entity;

                                if (targetEntity != null)

                                {

                                    if (pluginContext.SharedVariables.ContainsKey("flag"))

                                    {

                                        bool recievedFlag = (bool) pluginContext.SharedVariables["flag"];

                                        if (recievedFlag)

                                        {

                                        }

                                    }

                                }

                            }

                        }

This method lets you to pass data between plug-ins without having to customize the system by creating hidden fields on entities.

Note: SharedVariables (collection of key/value pairs) property is available in the IPluginExecutionContext of the execution pipeline.