Question

我的数据库中有五个条目＆＃34; Name＆＃34;这一切都始于＆＃39; pagetitle_dynamic _＆＃39;并有不同的后缀。我必须写一些不正确的东西，因为只返回一个结果。有什么建议吗？

public ActionResult PageList()
{
    var keys = db.Keys.ToList();
    var prefix = "pagetitle_dynamic_";
    var display = keys.Where(x => x.Name.StartsWith(prefix));

    foreach (var item in display)
    { 
        var viewModel = new PageListViewModel
        {
            PageTitle = item.Name
        };

        List<PageListViewModel> viewModelList = new List<PageListViewModel>();
        viewModelList.Add(viewModel);                   

        return View(viewModelList);
    }
}

Answer 1

您的代码格式不正确，如您所见。

foreach (var item in display)
{ 
      var viewModel = new PageListViewModel
      {
      PageTitle = item.Name
      };

      List<PageListViewModel> viewModelList = new List<PageListViewModel>();
      viewModelList.Add(viewModel);
      return View(viewModelList);
}

您已将return View(viewModelList);写入foreach循环，因为该方法仅在您将第一个列表成员添加到视图模型时结束。

一种可能的解决方案可能是：

public ActionResult PageList()
{
    List<PageListViewModel> viewModelList = new List<PageListViewModel>();
    var keys = db.Keys.ToList();
    var prefix = "pagetitle_dynamic_";
    var display = keys.Where(x => x.Name.StartsWith(prefix));

    foreach (var item in display)
    {
        var viewModel = new PageListViewModel
        {
            PageTitle = item.Name
        };

        viewModelList.Add(viewModel);
    }
    return View(viewModelList);
}

Answer 2

作为@blorgbeard mentioned，您需要在循环之外移动返回调用和列表构造。

public ActionResult PageList()
{
    var keys = db.Keys.ToList();
    var prefix = "pagetitle_dynamic_";
    var display = keys.Where(x => x.Name.StartsWith(prefix));
    var viewModelList = new List<PageListViewModel>();

    foreach (var item in display)
    { 
         var viewModel = new PageListViewModel
        {
            PageTitle = item.Name
        };

        viewModelList.Add(viewModel);
    }

    return View(viewModelList);
}

Answer 3

你可以更轻松地做到：

public ActionResult PageList()
{
    var keys = db.Keys.ToList();
    var prefix = "pagetitle_dynamic_";
    var display = keys.Where(x => x.Name.StartsWith(prefix));
    var viewModelList = new List<PageListViewModel>();

    return View(display.Select(item => new PageListViewModel
        {
            PageTitle = item.Name
        }
    ).ToList());
}

Linq没有返回所有想要的数据

3 个答案: