原代码：
foreach (var item in pageData)
{
list.Add(new tn_Manager { UserName = item.UserName, IsAudit = item.IsAudit, CreateTime = item.CreateTime, RoleName = PublicQuery.GetRoleById(item.RoleId).Name });
}
改进之后：
var list = pageData.Select(item => new tn_Manager {UserName = item.UserName, IsAudit = item.IsAudit, CreateTime = item.CreateTime, RoleName = PublicQuery.GetRoleById(item.RoleId).Name}).ToList();
原文：https://www.cnblogs.com/axu92312/p/9671330.html