Html.DropDownList 和 PagedList 问题答案

【问题标题】：Html.DropDownList And PagedList problemsHtml.DropDownList 和 PagedList 问题
【发布时间】：2011-10-17 23:34:13
【问题描述】：

我有一个小问题。我正在写一个简单的 rss 阅读器。所以我有渠道和项目。这是项目的视图。所以我有一个 SelectedChannel，用户可以选择他想看到什么样的频道（因为默认情况下他会看到所有频道的所有项目）

`public ViewResult Index(string sortOrder, string currentFilter, 
        int? page, int? SelectedChannel)
    {

        var channels = from ch in db.Channels
                       orderby ch.Title
                       select ch;
        ViewBag.SelectedChannel = new SelectList(channels, "ChannelID", "Title", SelectedChannel);
        int channelID = SelectedChannel.GetValueOrDefault();

        ViewBag.DateSortParm = sortOrder == "Date" ? "Date desc" : "Date";
        if (Request.HttpMethod == "GET")
        {
            //page = 1;
        }
        else
        {
            page = 1;
        }
        var items = from i in db.Items
                    select i;
        if (SelectedChannel.HasValue)
        {
             items = from i in db.Items
                     where i.ChannelID.Equals(channelID)
                     select i;
        }
       ...
        return View(items.ToPagedList(pageIndex, pageSize));
    }`

这是来自 index.cshtml 的代码

@using (Html.BeginForm()) { <p>Select Channel: @Html.DropDownList("SelectedChannel", "All")   <input type="submit" value="Filter" /></p> }

问题是：当用户过滤 1 个频道时。很好。但不是页面（可能有很多页面）。因此，当用户尝试转到下一页时，过滤器参数会丢失。我看到所有项目的第二页。但我想查看 selectedChannel 的第二页（因为它再次变为空）。希望你能明白我的意思。谢谢你！

【问题讨论】：

你是如何构建寻呼机的？您如何导航到其他页面？

标签： c# asp.net-mvc-3 drop-down-menu pagedlist

【解决方案1】：

`<div> 
Page @(Model.PageCount < Model.PageNumber ? 0 : Model.PageNumber) 
of @Model.PageCount 
&nbsp; 
@if (Model.HasPreviousPage) 
{ 
    @Html.ActionLink("<<", "Index", new { page = 1, sortOrder = ViewBag.CurrentSort, currentFilter=ViewBag.CurrentFilter  }) 
    @Html.Raw("&nbsp;"); 
    @Html.ActionLink("< Prev", "Index", new { page = Model.PageNumber - 1, sortOrder = ViewBag.CurrentSort, currentFilter=ViewBag.CurrentFilter  }) 
} 
else 
{ 
    @:<< 
    @Html.Raw("&nbsp;"); 
    @:< Prev 
} 
&nbsp; 
@if (Model.HasNextPage) 
{ 
    @Html.ActionLink("Next >", "Index", new { page = Model.PageNumber + 1, sortOrder = ViewBag.CurrentSort, currentFilter=ViewBag.CurrentFilter  }) 
    @Html.Raw("&nbsp;"); 
    @Html.ActionLink(">>", "Index", new { page = Model.PageCount, sortOrder = ViewBag.CurrentSort, currentFilter=ViewBag.CurrentFilter  }) 
} 
else 
{ 
    @:Next > 
    @Html.Raw("&nbsp;") 
    @:>> 
}

这是 index.cshtml 的结尾

【讨论】：

【解决方案2】：

这就是我的做法，它的工作原理，希望有些工作

@using (Html.BeginForm()) { <p>Select Channel: @Html.DropDownList("SelectedChannel", "All") &nbsp; <input type="submit" value="Filter" /></p> }

@if (Model.HasNextPage) 
{ 
    @Html.ActionLink("Next >", "Index", new { page = Model.PageNumber + 1, sortOrder = ViewBag.CurrentSort, currentFilter=ViewBag.CurrentFilter ciudad = "param-channel" }, new { id = "mylinkNext"  }) 
    @Html.Raw("&nbsp;"); 
    @Html.ActionLink(">>", "Index", new { page = Model.PageCount, sortOrder = ViewBag.CurrentSort, currentFilter=ViewBag.CurrentFilter, ciudad = "param-channel" }, new { id = "mylinkLast"  }) 
} 


<script type="text/javascript">
    $(function () {
        $('#mylinkNext').click(function () {
            var channel = $("#SelectedChannel").val();
            this.href = this.href.replace("param-channel",encodeURIComponent(channel));
        });
    });
  $(function () {
        $('#mylinkLast').click(function () {
            var channel = $("#SelectedChannel").val();
            this.href = this.href.replace("param-channel",encodeURIComponent(channel));
        });
    });
    </script>

【讨论】：