在.net MVC中呈现列表的子列表 [英] Rendering a sublist of a list in .net MVC
问题描述
我仍在学习.net MVC,也许没有正确搜索我需要找到解决方案的东西.
I'm still learning .net MVC, and perhaps am not searching correctly for what I need to find a solution to.
简而言之,我在数据库中有一个表,其结构为:
In short, I have a table in the database that is structured as:
ID Category Subcategory FK
因此,每个类别以及每个子类别都可能出现多次,这对于该类别来说是唯一的.
So each category may appear multiple times, as well as each subcategory, which is unique to the category.
我想在如下视图中呈现菜单:
I want to render a menu in the view that looks like:
Category 1
Subcategory 1a
Subcategory 1b
Subcategory 1c
Category 2
Subcategory 2a
Subcategory 2b
以此类推.现在在控制器中,我有:
And so on. Right now in the controller I have:
var categories = db.Category
.Where(oa => oa.Category != "")
.GroupBy(oa => new { oa.Category, oa.Subcategory })
.Select(oa => oa.FirstOrDefault());
但是,我不确定如何执行视图中想要实现的目标.我知道我必须以某种方式遍历列表,但不确定如何.我知道它涉及以下方面:
However, I'm not sure how to do what I want to achieve in the view. I know I have to loop through the list somehow, but I'm not sure how. I know it involved something along the lines of:
@foreach (var item in Model)
{
<li>
<a id="@item.ID" href="#">@item.Category</a>
</li>
}
但是我只希望每个类别都出现一次,然后让所有子类别都出现在父类别下.还是我需要更改控制器及其发送数据的方式?
But I only want each category to appear once, and then need all subcategories to appear under the parent category. Or maybe I need to change the controller and how it sends the data?
推荐答案
首先创建一个简单的视图模型来表示您要在视图中显示的内容
Start by creating a simple view model to represent what you want to display in the view
public class CategoryVM
{
public string Name { get; set; }
public IEnumerable<string> SubCategories { get; set; }
}
然后将查询投影到该视图模型的集合中,然后将其返回到视图
Then project your query to a collection of that view model and return it to the view
var model = db.Category.Where(x => x.Category != "")
.GroupBy(x => x.Category).Select(x => new CategoryVM
{
Name = x.Key,
SubCategories = x.Select(y => y.Subcategory)
});
return View(model);
并在视图中
@model IEnumerable<CategoryVM>
....
@foreach(var category in Model)
{
<h2>@category.Name</h2>
<ul>
@foreach(var subCategory in category.SubCategories)
{
<li>@subCategory</li>
}
</ul>
}
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