/// <summary>
        /// Executes the plug-in.
        /// </summary>
        /// <param name="localContext">The <see cref="LocalPluginContext"/> which contains the
        /// <see cref="IPluginExecutionContext"/>,
        /// <see cref="IOrganizationService"/>
        /// and <see cref="ITracingService"/>
        /// </param>
        /// <remarks>
        /// For improved performance, Microsoft Dynamics CRM caches plug-in instances.
        /// The plug-in's Execute method should be written to be stateless as the constructor
        /// is not called for every invocation of the plug-in. Also, multiple system threads
        /// could execute the plug-in at the same time. All per invocation state information
        /// is stored in the context. This means that you should not use global variables in plug-ins.
        /// </remarks>
        protected void ExecutePreValidateOpportunityDelete(LocalPluginContext localContext)
        {
            if (localContext == null)
            {
                throw new ArgumentNullException("localContext");
            }

            IPluginExecutionContext context = localContext.PluginExecutionContext;
            IOrganizationService    service = localContext.OrganizationService;
            ITracingService         trace   = localContext.TracingService;
            var opportunity = (EntityReference)context.InputParameters["Target"];

            try
            {
                EntityCollection opportuntiyCollection = CommonHandler.RetrieveRecordsByOneValue("opportunity", "opportunityid", opportunity.Id, service,
                                                                                                 null, OrderType.Ascending, new[] { "opportunityid" });

                OpportunityHandler opportunityHandler = new OpportunityHandler(service, trace);
                opportunityHandler.ValidateDelete(opportuntiyCollection.Entities[0]);
            }

            catch (Exception ex)
            {
                throw new InvalidPluginExecutionException(ex.Message);
            }
        }