c# - 无法添加到 IPagedList 对象或将 List 传输到 IPagedList

Question

我正在使用 Page List ASP MVC 插件将分页添加到我的 View ，因为我的 View 模型包含一个有时会有点失控的列表。但是，我遇到了一些问题。

• View 模型包含一个 List<T>另一个模型对象。如果我对数据库进行一次查询，我可以将此列表的数据类型从 List<ZipCodeTerritory> 更改为至 IPagedList<ZipCodeTerritory> ，然后只需按照文档从查询中加载列表，如下所示:

查看模型

public IPagedList<ZipCodeTerritory> zipCodeTerritory { get; set; }

Controller

search.zipCodeTerritory = (from z in db.ZipCodeTerritory
                          where z.StateCode.Equals(search.searchState) &&
                                z.EffectiveDate >= effectiveDate
                         select z).ToList().ToPagedList(pageNumber, pageSize);

//This works but this only covers one of the three different searches that are 
//possibly from this Index page

• 但是，这会带来一些问题。首先，我无法使用 .clear方法a C# List使用。其次，更重要的是，如果我需要执行不同的搜索，我会多次访问数据库并将每个查询的结果添加到 zipCodeTerritory 中。列表，我无法调用 .addRange()方法。有谁知道如何将项目添加到 IPagedList ？

查看模型

public IPagedList<ZipCodeTerritory> zipCodeTerritory { get; set; }

Controller

foreach (var zip in zipArray)
{
    var item = from   z in db.ZipCodeTerritory
                where  z.ZipCode.Equals(zip) &&
                        z.EffectiveDate >= effectiveDate &&
                        z.IndDistrnId.Equals(search.searchTerritory) &&
                        z.StateCode.Equals(search.searchState)
                select z;
    search.zipCodeTerritory.AddRange(item); //This line throws the following exception:

    //PagedList.IPagedList<Monet.Models.ZipCodeTerritory>' does not contain a 
    //definition for 'AddRange' and no extension method 'AddRange' accepting a first 
    //argument of type 'PagedList.IPagedList<Monet.Models.ZipCodeTerritory>' could be 
    //found (are you missing a using directive or an assembly reference?)
} 

• 我还尝试过在添加分页之前简单地保留代码，然后尝试转换 List<T>进入 IPagedList<T>对象，但是这也不起作用。这种方法可以解决我上面所有的问题，所以如果有人知道如何简单地转换 List和IPagedList那将不胜感激。

查看模型

    public IPagedList<ZipCodeTerritory> pagedTerritoryList { get; set; }
    public List<ZipCodeTerritory> zipCodeTerritory { get; set; }

Controller

search.pagedTerritoryList = (IPagedList<ZipCodeTerritory>)search.zipCodeTerritory;

//This threw the following exception at runtime: 
//Unable to cast object of type  
//System.Collections.Generic.List'1[Monet.Models.ZipCodeTerritory]' to type 
//'PagedList.IPagedList'1[Monet.Models.ZipCodeTerritory]'.

Answer 1

要将各种方法结合在一起，您可能应该这样做(基于您的第一个示例):

var mySearch = (from z in db.ZipCodeTerritory
                      where z.StateCode.Equals(search.searchState) &&
                            z.EffectiveDate >= effectiveDate
                     select z);

// Other searches, whatever; use mySearch.AddRange() here

search.zipCodeTerritory = mySearch.ToPagedList(pageNumber, pageSize);