ASP.NET 核心 3.1 - 将 child 项目添加到剃须刀局部视图

Question

我是新手，我已经为此苦苦挣扎了好几天！

我想做的只是将一个 child 项目添加到 parent，然后刷新局部视图。我的问题是当代码放入 OnGetAddNewChildItem 方法时，PageModel class 上的绑定属性为空（它不是空的，它只是没有中的数据）所以我不能添加 child 到这个。为了尝试解决这个问题，我尝试将数据传递到方法中，但这是空的。

奇怪的是，在我正在处理的实际解决方案中，我什至无法将其放入 PageModel class 除非它是 PUT 或 POST - 但如果我可以让这个演示工作，我相信我能够让主要解决方案工作。

我的页面模型class

public class IndexModel : PageModel
    {
        private readonly ILogger<IndexModel> _logger;

        [BindProperty]
        public Header MyHeader { get; set; } = new Header();

        public IndexModel(ILogger<IndexModel> logger)
        {
            _logger = logger;
        }

        public void OnGet()
        {
            MyHeader.Id = 1;
            MyHeader.MyHeaderProperty = "HeaderTest1";
            
            MyHeader.MyChildPropertiesList.AddRange(
                new List<Child> {
                    new Child() { Id = 1, HeaderId = MyHeader.Id, MyChildProperty = "ChildTest1" },
                    new Child() { Id = 2, HeaderId = MyHeader.Id, MyChildProperty = "ChildTest2" },
                    new Child() { Id = 3, HeaderId = MyHeader.Id, MyChildProperty = "ChildTest3" }
                });
        }

        public PartialViewResult OnGetAddNewChildItem([FromBody] Header myHeader)
        {
            if (myHeader.MyChildPropertiesList == null)
                myHeader.MyChildPropertiesList = new List<Child>();

            myHeader.MyChildPropertiesList.Add(new Child
            {
                Id = 4,
                HeaderId = myHeader.Id,
                MyChildProperty = "ChildTest4"
            });

            var partialView = "_ListItemPartial";

            var myViewData = new ViewDataDictionary(new EmptyModelMetadataProvider(), new ModelStateDictionary()) { { partialView, myHeader.MyChildPropertiesList } };
            myViewData.Model = myHeader;

            var partialViewResult = new PartialViewResult()
            {
                ViewName = partialView,
                ViewData = myViewData,
            };

            return partialViewResult;
        }
    }

    public class Header
    {
        public int Id { get; set; }
        public string MyHeaderProperty { get; set; }
        public List<Child> MyChildPropertiesList { get; set; } = new List<Child>();
    }

    public class Child
    {
        public int Id { get; set; }
        public int HeaderId { get; set; }
        public string MyChildProperty { get; set; }
    }
}

我的页面

@page
@model IndexModel
@{
    ViewData["Title"] = "Home page";
}

<div class="text-center">
    <h1 class="display-4">Welcome</h1>
    <p>Learn about <a href="https://docs.microsoft.com/aspnet/core">building Web apps with ASP.NET Core</a>.</p>
</div>

<div>
    <a class="btn btn-sm btn-info text-white" onclick="AddItem()">Add Child Item</a>
</div>

<br />

<div>
    <div><b>MyHeaderProperty value:</b> @Model.MyHeader.MyHeaderProperty</div>
    <br />
    <div class="font-weight-bold">Child Items</div>
    <br />
    <div id="LineItemsPartial">
        <partial name="_ListItemPartial" model="@Model" />
    </div>

</div>

<script type="text/javascript">
    function AddItem() {
        var model = @Json.Serialize(Model.MyHeader);
        alert(JSON.stringify(model));
        $.ajax({
            type: "GET",
            url: "?handler=AddNewChildItem",
            data: JSON.stringify(model),
            dataType: "json",
            success: function (result) {
                alert("Success");
                $('#LineItemsPartial').html(result);
            },
            failure: function (result) {
                alert("Failed");
            }
        });
    }
</script>

我的部分观点

@model IndexModel


<table>
    @foreach (var myChildItem in Model.MyHeader.MyChildPropertiesList)
    {
        <tr>
            <td>@myChildItem.HeaderId</td>
            <td>@myChildItem.MyChildProperty</td>
        </tr>
    }
</table>

非常感谢任何帮助。

Answer 1

从你的代码设计来看，你有以下错误：

1.It在get中使用FromBody不是一个好方法method.If你想通过get请求向后端发送数据，你需要通过查询字符串发送模型您所做的 url.What 应该是 Post 请求方式。

参考：

2.The局部视图结果的ViewData是Header的类型。但是你的局部视图需要IndexModel

的类型

这是一个工作演示：

Index.cshtml:

@page
@model IndexModel
<div>
    <a class="btn btn-sm btn-info text-white" onclick="AddItem()">Add Child Item</a>
</div>
<br />
<div>
    <div><b>MyHeaderProperty value:</b> @Model.MyHeader.MyHeaderProperty</div>
    <br />
    <div class="font-weight-bold">Child Items</div>
    <br />
    <div id="LineItemsPartial">
        <partial name="_ListItemPartial" model="@Model" />
    </div>
    @Html.AntiForgeryToken()  @*add this*@
</div>

<script type="text/javascript">
    function AddItem() {
        var model = @Json.Serialize(Model.MyHeader);
        $.ajax({
            type: "Post",      //change this...
            url: "?handler=AddNewChildItem",
            data: JSON.stringify(model),
            
            //add the following contentType and headers..
            contentType: "application/json",  
            headers: {
                RequestVerificationToken: $('input:hidden[name="__RequestVerificationToken"]').val()
            },
            dataType: "html",     //midify this..
            success: function (result) {
                $('#LineItemsPartial').html(result);
            },
            failure: function (result) {
                alert("Failed");
            }
        });
    }
</script>

Index.cshtml.cs:

public class IndexModel : PageModel
{
    private readonly ILogger<IndexModel> _logger;

    [BindProperty]
    public Header MyHeader { get; set; } = new Header();

    public IndexModel(ILogger<IndexModel> logger)
    {
        _logger = logger;
    }

    public PartialViewResult OnPostAddNewChildItem([FromBody] Header myHeader)
    {
        if (myHeader.MyChildPropertiesList == null)
            myHeader.MyChildPropertiesList = new List<Child>();

        myHeader.MyChildPropertiesList.Add(new Child
        {
            Id = 4,
            HeaderId = myHeader.Id,
            MyChildProperty = "ChildTest4"
        });

        //add this line....
        var data = new IndexModel(_logger);
        data.MyHeader = myHeader;

        var partialView = "_ListItemPartial";

        var myViewData = new ViewDataDictionary(new EmptyModelMetadataProvider(), new ModelStateDictionary()) { { partialView, myHeader.MyChildPropertiesList } };
        myViewData.Model = data;   //change here..

        var partialViewResult = new PartialViewResult()
        {
            ViewName = partialView,
            ViewData = myViewData,
        };     
        return partialViewResult;
    }
}

结果：

ASP.NET 核心 3.1 - 将 child 项目添加到剃须刀局部视图

ASP.NET Core 3.1 - adding child item to razor partial view

c#

asp.net

asp.net-core

partial-views

razor-pages