在检查PLUGIN代码的时候发现如下一段获取组织服务的代码

// service provider.
this.Context =(IPluginExecutionContext)serviceProvider.GetService(typeof(IPluginExecutionContext));
// 访问组织服务
IOrganizationServiceFactory factory =(IOrganizationServiceFactory)serviceProvider.GetService(typeof(IOrganizationServiceFactory));
this.Service = factory.CreateOrganizationService(this.Context.UserId);
this.TracingService = (ITracingService)serviceProvider.GetService(typeof(ITracingService));
this.AdminService = factory.CreateOrganizationService(getAdminId());

一般我们在初始化Service的时候都是用的Context.UserId来初始化，也就是当前执行用户的身份。
但这里出现了一个AdminService，也就是强制用管理员的身份来初始化，实现方法是通过getAdminId()方法来获取admin的Id

Guid getAdminId()
{
            string fetch = string.Format(@"<fetch version='1.0' output-format='xml-platform' mapping='logical' distinct='false'>
                                              <entity name='systemuser'>
                                                <attribute name='fullname' />
                                                <attribute name='businessunitid' />
                                                <attribute name='title' />
                                                <attribute name='address1_telephone1' />
                                                <attribute name='systemuserid' />
                                                <order attribute='fullname' descending='false' />
                                                <filter type='and'>
                                                  <condition attribute='fullname' operator='eq' value='crmadmin1名' />
                                                </filter>
                                              </entity>
                                            </fetch> ");

            EntityCollection enities = Query.query.QueryByFetch(fetch, Service);

            //TracingService.Trace("enities.Entities.Count:" + enities.Entities.Count.ToString());
            if (enities.Entities.Count > 0)
            {
                //TracingService.Trace(enities.Entities[0].Id.ToString());
                return enities.Entities[0].Id;
            }
            else
            {
                return Guid.Empty;
            }
}

检查系统发现，系统中根本没有叫crmadmin1名的用户，也就是永远返回一个Guid.Empty,原以为这样会报错，但实际情况却是正常，没有报错出现。查询微软文档发现如下一段解释

IOrganizationService CreateOrganizationService (
    Nullable<Guid> userId
)

参数
userId
Type: 可为空值. Specifies the system user that calls to the service are made for. A Null value indicates the SYSTEM user. When called in a plug-in, a Guid.Empty value indicates the same user as IPluginExecutionContext. UserId. When called in a custom workflow activity, a Guid.Empty value indicates the same user as IWorkflowExecutionContext.UserId. Any other value indicates a specific system user.

也就是说可以直接传递一个Guid.Empty来初始化Service，并且如果是Guid.Empty那么其实和Context.UserId是同样的作用。