Question

我在这上面画了一个空白。我有两个foreach循环正在创建div并且我试图从第二个foreach获得一个或两个项目来显示来自第一个foreach的每两个项目....这里是代码..

@foreach (var stream in Model.LiveStreams)
{
    <div id="divLiveStream" class="well-livestream well-sm">
       <div class="row">
          <div class="col-md-2">
              <div class="ui-icon-image">
                  <img src="~/Images/placeholder.jpg" width="100%" />
              </div>
          </div>
          <div class="col-md-10">
              <div class="text-left row">
                  <div class="col-md-12">
                         @stream.UserName
                  </div>
                  <div class="col-md-12">
                         @stream.Status
                   </div>
              </div>
          </div>
       </div>
    </div>
}
@foreach (var post in Model.LivePosts)
{
   <div id="divLivePost" class="well-liveposts well-sm">
     <div class="row">
          <div class="col-md-2">
              <div class="ui-icon-image">
                  <img src="~/Images/placeholder.jpg" width="100%" />
              </div>
          </div>
          <div class="col-md-10">
              <div class="text-left row">
                  <div class="col-md-12">
                       @post.AspNetUser.UserName
                  </div>
                  <div class="col-md-12">
                       @post.PostDescription
                  </div>
              </div>
         </div>
     </div>
  </div>
}

因此，为了进一步说明，我尝试显示2个divLiveStream，然后显示2个divLivePost，并继续使用该模式。我是MVC的新手，所以我不知道如何解决这个问题，而且我在本周五画了各种空白..提前谢谢！

编辑：这是我的ViewModel。

public class LiveStreamViewModel
{
    public IEnumerable<LiveStream> LiveStreams { get; set; }

    public IEnumerable<tPost> LivePosts { get; set; }
}

编辑：可能是一个愚蠢的问题，但我使用我的控制器返回模型。在我拥有下面的控制器之前，我怎么想调用你在控制器中创建的新ViewModel？这是我的控制器。

public ActionResult LiveStream()
{
    Service service = new Service();
    LiveStreamViewModel model = new LiveStreamViewModel
    {
        LiveStreams = service.GetLiveStream(),
        LivePosts = service.GetLivePosts()
    };
    if (TempData["Message"] != null) ViewBag.Message = TempData["Message"]; ViewBag.Header = "Success!";

     return View(model);
    }
}

我的数据服务。

public IEnumerable<LiveStream> GetLiveStream()
{
    using (dboMyJeepTraderEntities context = new dboMyJeepTraderEntities())
    {
        return (from s in context.tStatusUpdates select new LiveStream 
        { 
            Status = s.Status,
            UserName = s.AspNetUser.UserName
        }).ToList();
    }

}

public IEnumerable<tPost> GetLivePosts()
{
    return (from p in _context.tPosts select p).ToList();
}

Answer 1

您需要一个视图模型，并且视图模型的水合会发生更改。

public abstract class AbstractThing
{
    public abstract string TheUserName { get; }
    public abstract string TheDescription { get; }
}

public class LivePost : AbstractThing
{
    public string UserName { get; set; }
    public string PostDescription { get; set; }

    public override string TheUserName
    {
        get { return this.UserName; }
    }

    public override string TheDescription
    {
        get { return this.PostDescription; }
    }
}


public class LiveStream : AbstractThing
{
    public string UserName { get; set; }
    public string Status { get; set; }

    public override string TheUserName
    {
        get { return this.UserName; }
    }

    public override string TheDescription
    {
        get { return this.Status; }
    }

}


public class AlternatingThingsViewModel
{

    public ICollection<AbstractThing> AbstractThings { get; private set; }

    public AlternatingThingsViewModel(ICollection<LivePost> lps, ICollection<LiveStream> lss)
    {

        this.AbstractThings = new List<AbstractThing>();

        /* this is not correct...here is where you would "two by two" add items to the this.AbstractThings in the order you want.  the key is to have one collection exposed by the viewmodel */

        if (null != lps)
        {
            foreach (AbstractThing at in lps)
            {
                this.AbstractThings.Add(at);
            }
        }

        if (null != lss)
        {
            foreach (AbstractThing at in lss)
            {
                this.AbstractThings.Add(at);
            }
        }

    }
}

现在循环单个集合

@foreach (var post in Model.AbstractThings)
{
   <div id="divLivePost" class="well-liveposts well-sm">
     <div class="row">
          <div class="col-md-2">
              <div class="ui-icon-image">
                  <img src="~/Images/placeholder.jpg" width="100%" />
              </div>
          </div>
          <div class="col-md-10">
              <div class="text-left row">
                  <div class="col-md-12">
                       @post.TheUserName
                  </div>
                  <div class="col-md-12">
                       @post.TheDescription
                  </div>
              </div>
         </div>
     </div>
  </div>
}

以下是“一个接一个”的实现......只要LivePost计数大于LiveStream。并没有错误检查。但是给你一个想法。

public class AlternatingThingsViewModel
{

    public ICollection<AbstractThing> AbstractThings { get; private set; }

    public AlternatingThingsViewModel(ICollection<LivePost> lps, ICollection<LiveStream> lss)
    {
        this.AbstractThings = new List<AbstractThing>();
        /* this is a "one by one" with no error checking if the counts are different */

        IEnumerator<AbstractThing> livePostEnum = null == lps ? null : lps.GetEnumerator();
        IEnumerator<AbstractThing> liveStreamEnum = null == lss ? null : lss.GetEnumerator();

        if (null != liveStreamEnum)
        {
            liveStreamEnum.MoveNext();
        }

        if (null != livePostEnum)
        {
            while (livePostEnum.MoveNext() == true)
            {
                AbstractThing lpCurrent = livePostEnum.Current;
                AbstractThing lsCurrent = null == liveStreamEnum ? null : liveStreamEnum.Current;
                if (null != liveStreamEnum)
                {
                    liveStreamEnum.MoveNext();
                }

                this.AbstractThings.Add(lpCurrent);
                if (null != lsCurrent)
                {
                    this.AbstractThings.Add(lsCurrent);
                }
            }
        }
    }
}

和一些调用代码。

    static void Main(string[] args)
    {

        try
        {

            ICollection<LivePost> lps = new List<LivePost>();
            lps.Add(new LivePost() { UserName = "LivePostUserName1", PostDescription = "LivePostDescription1" });
            lps.Add(new LivePost() { UserName = "LivePostUserName2", PostDescription = "LivePostDescription2" });
            lps.Add(new LivePost() { UserName = "LivePostUserName3", PostDescription = "LivePostDescription3" });
            lps.Add(new LivePost() { UserName = "LivePostUserName4", PostDescription = "LivePostDescription4" });

            ICollection<LiveStream> lss = new List<LiveStream>();
            lss.Add(new LiveStream() { UserName = "LiveStreamUserName1", Status = "LiveStreamStatus1" });
            lss.Add(new LiveStream() { UserName = "LiveStreamUserName2", Status = "LiveStreamStatus2" });
            //lss.Add(new LiveStream() { UserName = "LiveStreamUserName3", Status = "LiveStreamStatus3" });


            AlternatingThingsViewModel atmv = new AlternatingThingsViewModel(lps, lss);

            int modCheckCount = 0;
            foreach (AbstractThing at in atmv.AbstractThings)
            {
                Console.WriteLine("{0}, {1}", at.TheUserName, at.TheDescription);

                if (++modCheckCount % 2 == 0)
                {
                    Console.WriteLine("");
                }
            }

Answer 2

嗯，所以 - 是的 - 在Controller中做这件事显然是有道理的。但是，再一次，Razor只是（大部分）C＃所以无论你能做什么，你都可以做到另一个：

@{
    var streamIndex = 0;
    var postIndex = 0;
}
@while (streamIndex < Model.LiveStreams.Count() || postIndex < Model.LivePosts.Count()) {
    @foreach (var stream in Model.LiveStreams.Skip(streamIndex).Take(2)) {
       // html code
       streamIndex++;
    }
    @foreach (var post in Model.LivePosts.Skip(postIndex).Take(2)) {
       // html code
       postIndex++;
    }
}

如何在Razor语法中的两个不同列表之间交替？

2 个答案: