我有一个视图模型对象，其中包含另一个模型对象类型的List。当用户在页面上进行查询时，如果返回的List包含超过300条记录，我们希望使用分页来减少加载时间（某些搜索结果可以返回超过14k条记录）。我们正在使用的分页插件can be found here.
一旦结果显示在页面上，用户就可以单击特定结果旁边的复选框，在输入文本框中键入一些信息，点击提交，并使用信息编辑选定的记录从文本框中。
由于我们需要使用IPagedList<>来启用分页，但是当您点击提交时（在页面甚至命中控制器之前），我们会收到以下错误：
Cannot create an instance of an interface.
查看模型
这是我们用于分页的两个列表对象。 zipCodeTerritory对象保存查询结果。 pagedTerritoryList用于仅显示用户所在特定页面上的结果。
//Paging List objects
public IPagedList<ZipCodeTerritory> pagedTerritoryList { get; set; }
public List<ZipCodeTerritory> zipCodeTerritory { get; set; }
public IPagedList PagingMetaData { get; set; }
控制器
这是我们的基本搜索。 .ToPagedList方法用于指定我们想要显示的结果范围，并将它们放在pagedTerritoryList对象中。
//set Paged List counter variables
int pageNumber = page ?? 1;
int pageSize = 300;
//Determine if Territory present?
if (string.IsNullOrWhiteSpace(search.searchTerritory))
{
//State Code ONLY search
search.zipCodeTerritory = (from z in db.ZipCodeTerritory
where z.StateCode.Equals(search.searchState)
select z).ToList();
}
else if(string.IsNullOrWhiteSpace(search.searchState))
{
//Territory ONLY search
search.zipCodeTerritory = (from z in db.ZipCodeTerritory
where z.IndDistrnId.Equals(search.searchTerritory)
select z).ToList();
}
else
{
//Territory AND state search
search.zipCodeTerritory = (from z in db.ZipCodeTerritory
where z.IndDistrnId.Equals(search.searchTerritory) &&
z.StateCode.Equals(search.searchState)
select z).ToList();
}
//Convert list to IPagedList for pagining on Index
search.pagedTerritoryList = search.zipCodeTerritory.ToPagedList(pageNumber, pageSize);
//Set Paged List objects
search.PagingMetaData = new StaticPagedList<ZipCodeTerritory>(search.zipCodeTerritory, pageNumber, pageSize,
search.zipCodeTerritory.Count).GetMetaData();
return View(search);
查看
这是显示搜索结果的表单。如果用户选中复选框，然后点击clone或delete按钮，则结果应该回发到控制器的Update方法，并执行适当的编辑或删除。用户希望在编辑中叠加的信息将输入到表单中的newTerritory/Description/etc字段中（table上方）。
关于@Html.PagedListPager我发现我必须从页面返回索引方法相同的搜索条件，因此RouteValueDictionary中的参数过多。
@if (Model.zipCodeTerritory.Count > 0)
{
using (Html.BeginForm("Update", "ZipCodeTerritory", FormMethod.Post))
{
@Html.HiddenFor(model => model.searchZip)
@Html.HiddenFor(model => model.searchDate)
@Html.HiddenFor(model => model.searchState)
<div id="cloneBox">
<div id="rw1">
@Html.LabelFor(model => model.newTerritory)
@Html.TextBoxFor(model => model.newTerritory, new { style = "width: 30px;padding-left:10px;", maxLength = 3 })
@Html.LabelFor(model => model.newDescription)
@Html.TextBoxFor(model => model.newDescription, new { style = "width: 250px;padding-left:10px;", maxLength = 30 })
@Html.LabelFor(model => model.newEffectiveDate)
@Html.TextBoxFor(model => model.newEffectiveDate, new { style = "width: 80px;padding-left:10px;" })
<div id="rw2" style="padding-top: 10px;">
@Html.LabelFor(model => model.newChannelCode)
@Html.DropDownListFor(model => model.newChannelCode, Model.ChannelCodes, " ")
@Html.LabelFor(model => model.newStateCode)
@Html.DropDownListFor(model => model.newStateCode, Model.StateCodes, " ")
</div>
</div>
</div>
<br/>
<div id="buttonDiv">
<button type="submit" id="CloneButton" name="button" value="clone">Apply New Data</button>
<button type="submit" id="deleteButton" name="button" value="delete">Delete Selected Items</button>
</div>
@*Display paging only if necessary*@
if (Model.pagedTerritoryList.Count >= 300)
{
<div id="pagingDiv">
@Html.PagedListPager(new StaticPagedList<Monet.Models.ZipCodeTerritory>(Model.zipCodeTerritory, Model.PagingMetaData) ,
Page => Url.Action("Index", new RouteValueDictionary()
{
{ "Page", Page},
{ "searchZip", Model.searchZip },
{ "searchActiveOnly", Model.searchActiveOnly },
{ "searchDate", Model.searchDate },
{ "searchState", Model.searchState },
{ "searchTerritory", Model.searchTerritory },
{ "searchChannel" , Model.searchChannelCode }
}), PagedListRenderOptions.DefaultPlusFirstAndLast)
</div>
}
<table id="thetable" class="tablesorter" >
<thead>
<th>@Html.CheckBox("SelectAll")</th>
<th>State</th>
<th>Territory</th>
<th>Zip</th>
<th>Description</th>
<th>Effective</th>
<th>End Date</th>
<th>Last Update Date</th>
<th>Channel</th>
<th></th>
</thead>
<tbody id="tableBody">
@for (int i = 0; i < Model.pagedTerritoryList.Count; i++)
{
<tr id="@(Model.lastEditedId == Model.pagedTerritoryList[i].Id ? "lastEdit" : "")">
<td>
@Html.CheckBoxFor(model => model.pagedTerritoryList[i].Update)
@Html.HiddenFor(model => model.pagedTerritoryList[i].Update)
</td>
<td>
@Html.DisplayFor(model => model.pagedTerritoryList[i].StateCode)
@Html.HiddenFor(model => model.pagedTerritoryList[i].StateCode)
</td>
<td>
@Html.DisplayFor(model => model.pagedTerritoryList[i].IndDistrnId)
@Html.HiddenFor(model => model.pagedTerritoryList[i].IndDistrnId)
</td>
<td>
@Html.DisplayFor(model => model.pagedTerritoryList[i].ZipCode)
@Html.HiddenFor(model => model.zipCodeTerritory[i].ZipCode)
</td>
<td>
@Html.DisplayFor(model => model.pagedTerritoryList[i].DrmTerrDesc)
@Html.HiddenFor(model => model.pagedTerritoryList[i].DrmTerrDesc)
</td>
<td>
@Html.DisplayFor(model => model.pagedTerritoryList[i].EffectiveDate)
@Html.HiddenFor(model => model.pagedTerritoryList[i].EffectiveDate)
</td>
<td>
@if (Model.pagedTerritoryList[i].EndDate.Date != DateTime.MaxValue.Date)
{
@Html.DisplayFor(model => model.pagedTerritoryList[i].EndDate)
@Html.HiddenFor(model => model.pagedTerritoryList[i].EndDate)
}
</td>
<td>
@Html.DisplayFor(model => model.pagedTerritoryList[i].LastUpdateDate)
@Html.HiddenFor(model => model.pagedTerritoryList[i].LastUpdateDate)
</td>
<td>
@Html.DisplayFor(model => model.pagedTerritoryList[i].ChannelCode)
@Html.HiddenFor(model => model.pagedTerritoryList[i].ChannelCode)
</td>
@if (ViewBag.SecurityLevel >= 4)
{
<td>
@Html.ActionLink("Edit", "Edit", new
{
id = Model.zipCodeTerritory[i].Id,
searchZip = Model.searchZip,
searchActiveOnly = Model.searchActiveOnly,
searchDate = Model.searchDate,
searchState = Model.searchState,
searchTerritory = Model.searchTerritory,
searchChannelCode = Model.searchChannelCode
})
@Html.HiddenFor(model => model.zipCodeTerritory[i].Id)
</td>
}
</tr>
}
</tbody>
</table>
}
}
修改
根据下面的评论，这是表单发布到的方法的签名。它包含最初在页面上加载的ZipCodeIndex的实例，以及来自button的文本，以确定我们是在执行clone还是delete
[HttpPost]
public ActionResult Update(ZipCodeIndex updateZip, string button)
{
第二次修改
从this question尝试了该方法，但仍然收到原始错误消息（“无法创建接口实例”）。
答案 0 :(得分：5)
我能完全破解我的方式，但我不认为这是最好的解决方案。如果有人可以提供更好的答案，我会喜欢它，但我会在此期间将其发布到此处。
由于IPagedList对象是为了保存List<>的特定范围而构建的，所以我在视图模型上创建了一个显示属性，并在我的视图中使用了它。此列表（而不是IPagedList）会回发给控制器以进行更新，因此不会出现界面怪异现象。
查看模型
//Paging List objects
public IPagedList<ZipCodeTerritory> pagedTerritoryList { get; set; }
public List<ZipCodeTerritory> zipCodeTerritory { get; set; }
public List<ZipCodeTerritory> displayForPaging { get; set; }
<强>控制器
//Convert list to IPagedList for pagining on Index
search.pagedTerritoryList = search.zipCodeTerritory.ToPagedList(pageNumber, pageSize);
search.displayForPaging = search.pagedTerritoryList.ToList();
查看
<td>
@Html.CheckBoxFor(model => model.displayForPaging[i].Update)
@Html.HiddenFor(model => model.displayForPaging[i].Update)
</td>
<td>
.
.
答案 1 :(得分：0)
我发现将接口作为属性的模型需要创建一个ModelBinder来确定要使用的实现。
ASP.Net MVC Custom Model Binding explanation
基本上，您的活页夹会为您解析您的模型，确定哪种类型的IPagedList＆lt;＆gt;实施。