处理操作前插件以更新MSCRM中的"Modified By“字段--需要帮助修复代码

using Microsoft.Xrm.Sdk;
using Microsoft.Xrm.Sdk.Query;

public class UpdateModifiedByPlugin : IPlugin
{
    public void Execute(IServiceProvider serviceProvider)
    {
        // 获取上下文和服务
        IPluginExecutionContext context = (IPluginExecutionContext)serviceProvider.GetService(typeof(IPluginExecutionContext));
        IOrganizationServiceFactory serviceFactory = (IOrganizationServiceFactory)serviceProvider.GetService(typeof(IOrganizationServiceFactory));
        IOrganizationService service = serviceFactory.CreateOrganizationService(context.UserId);

        // 获取当前用户信息
        Guid currentUserId = context.UserId;
        EntityReference currentUserRef = new EntityReference("systemuser", currentUserId);

        // 获取需要更新的记录ID
        Guid recordId = ((Entity)context.InputParameters["Target"]).Id;

        // 更新"Modified By"字段
        Entity record = new Entity("your_entity_name", recordId);
        record["modifiedby"] = currentUserRef;
        service.Update(record);
    }
}