模型：

public class Book
{
    public string Id { get; set; }

    public string Name { get; set; }
}

public class Comment
{
    public string Id { get; set; }

    public string BookId { get; set; }

    public string Content { get; set; }    
}

控制器：

public IActionResult Detail(string id)
{
    ViewData["DbContext"] = _context; // DbContext

    var model = ... // book model

    return View(model);
}

视图：

详细视图：

@if (Model?.Count > 0)
{
    var context = (ApplicationDbContext)ViewData["DbContext"];
    IEnumerable<Comment> comments = context.Comments.Where(x => x.BookId == Model.Id);

    @Html.Partial("_Comment",comments)
}

评论局部视图：

@model IEnumerable<Comment>

@if (Model?.Count > 0)
{
    <!-- display comments here... -->
}

<-- How to get "BookId" here if Model is null? -->

我试过这个：

@Html.Partial("_Comment",comments,new ViewDataDictionary { { "BookId",Model.Id } })

然后

@{
    string bookid = ViewData["BookId"]?.ToString() ?? "";
}

@if (Model?.Count() > 0)
{
    <!-- display comments here... -->
}

<div id="@bookid">
    other implements...
</div>

但是错误：

‘ViewDataDictionary’ does not contain a constructor that takes 0
arguments

当我选择ViewDataDictionary并按F12时,它会命中：

namespace Microsoft.AspNetCore.Mvc.ViewFeatures
{
    public ViewDataDictionary(IModelMetadataProvider MetadataProvider,ModelStateDictionary modelState);
}

我不知道什么是IModelMetadataProvider和ModelStateDictionary？

我的目标：将视图Detail.cshtml中的模型注释发送到部分视图_Comment.cshtml,其中包含一个包含BookId的ViewDataDictionary.

我的问题：我怎么能这样做？