使用 LInq to SQL 从 ASP.NET 会员资格获取所有用户电子邮件

Question

public ActionResult DownloadMembers()
{
    MembershipUserCollection users = Membership.GetAllUsers();
    var grid = new WebControls.GridView();
    grid.DataSource = from members in users  // the users gives error
                      select new
                      {
                          Name = members.FirstName, // This doesn't works
                          Email = members.Email     //  This doesn't works
                      };
    grid.DataBind();
    Response.ClearContent();
    Response.AddHeader("content-disposition", "attachment; filename=" + "Members" + ".xls");
    Response.ContentType = "application/excel";
    StringWriter sw = new StringWriter();
    HtmlTextWriter htw = new HtmlTextWriter(sw);
    grid.RenderControl(htw);
    Response.Write(sw.ToString());
    Response.End();
    return RedirectToAction("Index");
}

您好，上面的查询将会员资格表中的所有详细信息下载为 MS Excel 的 CSV 格式，它给用户带来了一个错误：

找不到源类型“System.Web.Security.MembershipUserCollection”的查询模式的实现。未找到“选择”。考虑显式指定范围变量“成员”的类型。

任何人都可以指导我如何仅获取 csv 上的用户电子邮件地址和他/她的姓名，而不是获取所有详细信息。

编辑：这有效:)

grid.DataSource = from MembershipUser u in Membership.GetAllUsers()
                  select new
                  {
                      Firstname = u.UserName,
                      Email = u.Email                                   
                  };

Answer 1

grid.DataSource = (from members in users  
                   select new
                   {
                       Name = members.FirstName,
                       Email = members.Email    
                   }).ToList();

我认为您需要调用 ToList() 因为 LINQ 会延迟加载，因此通过调用 ToList() 您实际上是显式强制加载数据。

Answer 2

grid.DataSource = from members in users  
                  select new
                  {
                      Name = members.FirstName,
                      Email = members.Email    
                  };

Answer 3

grid.DataSource = from MembershipUser u in Membership.GetAllUsers()
              select new
              {
                  Firstname = u.UserName,
                  Email = u.Email                                   
              };

上面的 linqQuery 工作正常。