C# 在类控制器中将icollection设置为列表时,如何通过索引从icollection获取项?
我有一组消息,每个消息由以下内容定义:C# 在类控制器中将icollection设置为列表时,如何通过索引从icollection获取项?,c#,asp.net-mvc,entity-framework,asp.net-mvc-5,C#,Asp.net Mvc,Entity Framework,Asp.net Mvc 5,我有一组消息,每个消息由以下内容定义: namespace DatabaseDesign.Models { public class PrivateMessageDetail { public int PrivateMessageDetailId { get; set; } public DateTime MessageDate { get; set; } public string FromUser { get; set; } /
namespace DatabaseDesign.Models
{
public class PrivateMessageDetail
{
public int PrivateMessageDetailId { get; set; }
public DateTime MessageDate { get; set; }
public string FromUser { get; set; } // Don't need ToUser, it's already in header
public string Message { get; set; }
public int PrivateMessageHeaderId { get; set; }
public virtual PrivateMessageHeader PrivateMessageHeader { get; set; }
}
}
两个用户之间的消息集合保存在messages iCollection中,它被重新定义(我想?)为此类构造函数中的列表:
namespace DatabaseDesign.Models
{
public class PrivateMessageHeader
{
public int PrivateMessageHeaderId { get; set; }
public PrivateMessageHeader() { this.Messages = new List<PrivateMessageDetail>(); }
public DateTime TimeStamp { get; set; } // Date of the start of thread
public string User1 { get; set; }
public string User2 { get; set; } // this could be made to a list to allow multiples
public int numberOfMessages { get; set; }
public virtual ICollection<PrivateMessageDetail> Messages { get; set; }
}
}
线路
var MsgHistory = PrivateMessageRepository.GetMessageHistoryByID(userTo, userFrom);
返回正确的PrivateMessageHeader(即2个用户之间的消息历史记录)。不过,我似乎无法把数据拿出来
尝试1:我通过viewbag传递了整个过程,并试图通过这种方式取出数据。在经历了5分钟的挫折之后,我觉得这可能不是最好的方法。当然,将数据存储为字符串并查看那个坏小子的包会更有效吗
因此,我继续做了当前显示在Details controller中的事情,并尝试访问Messages List/iCollection中保存的PrivateMessageDetails。但我不会在foreach循环中为它们编制索引,因为我说iCollection不能以这种方式引用。。。。但在《建筑商》中,我把它定义为一个列表
我的问题是:
var MsgHistory = PrivateMessageRepository.GetMessageHistoryByID(userTo, userFrom);
string MsgStr = "";
foreach (var msg in MsgHistory.Messages)
{
MsgStr += MsgHistory.Messages[msg].UserFrom +": "+MsgHistory.Messages[msg].Message+"<br>";
}
Viewbag.Message = MsgStr;
return View();
var MsgHistory=PrivateMessageRepository.GetMessageHistoryByID(userTo,userFrom);
字符串MsgStr=“”;
foreach(MsgHistory.Messages中的var msg)
{
MsgStr+=MsgHistory.Messages[msg].UserFrom+“:“+MsgHistory.Messages[msg].Message+”
”;
}
Viewbag.Message=MsgStr;
返回视图();
无需尝试访问MsgHistory.Messages
,就好像它是一个列表一样。a中的迭代器变量是正在循环的列表中的当前项。因此,您不需要从列表中获取该项。试试这个:
foreach (var msg in MsgHistory.Messages)
{
MsgStr += msg.UserFrom + ": " + msg.Message + "<br>";
}
并在视图中按如下方式构造HTML:
public ActionResult Details()//string userTo, string userFrom)
{
var MsgHistory = PrivateMessageRepository.GetMessageHistoryByID(userTo, userFrom);
var viewModel = MsgHistory.Messages.ToList();
return View(viewModel);
}
@model IEnumerable<DatabaseDesign.Models.PrivateMessageDetail>
...
@foreach(var msg in Model) {
@:@msg.UserFrom: @msg.Messages<br>
}
使用动态
视图模型:
@model IEnumerable<dynamic>
...
@foreach(var msg in Model) {
@:@msg.UserFrom: @msg.Messages<br>
}
@model IEnumerable
...
@foreach(模型中的var msg){
@:@msg.UserFrom:@msg.Messages
}
你好,非常感谢!我认为它几乎可以工作了,但当我在@model IEnumerable的顶行执行该操作时,我会得到“您是否缺少程序集引用?”MsgHistory变量返回整个消息历史记录,即键入PrivateMessageHeader,而不是PrivateMessageDetail,因此我认为需要进行一些更改。@user2330270您缺少名称空间(DatabaseDesign.Models
)但我的控制器逻辑也有错误。请参阅我的更新答案。
public ActionResult Details()//string userTo, string userFrom)
{
var MsgHistory = PrivateMessageRepository.GetMessageHistoryByID(userTo, userFrom);
var viewModel = MsgHistory.Messages.Select(x => new { x.UserFrom, x.Message }).ToList();
return View(viewModel);
}
@model IEnumerable<dynamic>
...
@foreach(var msg in Model) {
@:@msg.UserFrom: @msg.Messages<br>
}