提交 ASP.NET Core 3.1 MVC 后填充表单字段

Question

我正在尝试在提交表单后重新填充我的输入字段（使用 HttpPost）。有没有一种简单的方法可以做到这一点？我有一个下拉列表和一个文本框，其中填充了数据库中的数据。它们在控制器中都有自己的函数来处理数据流。我的目标是在提交后让最后创建的数据出现在输入字段中。

我的模特

public int ID { get; set; }
public string bookName { get; set; }
public string Author { get; set; }

我的观点

<form method="post" asp-controller="Home" asp-action="Home" role="post">
    <div class="form-group">
        <label asp-for="bookName"></label>
        <select name="bookName" asp-items="@(new SelectList(ViewBag.message, "ID", "bookName"))">
</select>
    </div>
    <div class="form-group">
        <label asp-for="Author"></label>
        <input asp-for="Author" class="form-control" />
    </div>
    <div class="form-group">
        <input type="submit" value="Submit" class="btn btn-primary" />
    </div>
</form>

我的控制器

        public void GetBooksDDL()
        {
            List<BookModel> bookName = new List<BookModel>();
            bookName = (from b in _context.BookModel select b).ToList();
            bookName.Insert(0, new BookModel { ID = 0, bookName = "" });
            ViewBag.message = bookName;
        }

        [HttpPost("[action]")]
        [Route("/Home")]
        [Produces("application/json")]
        public async Task<IActionResult> Home()
        {
            if (textbox != "")
            {
                //do all the submit actions
                //after all of the actions are complete return the view:
                GetBooksDDL();
                return View();
            }else
            {
                return Error;
            }
        }

我知道我可以在 View() 中传入模型，但值始终为空。我试图将我的（BookModel 模型）作为参数传入 HttpPost，但我得到了 415 状态。

Answer 1

我正在尝试在提交表单后重新填充我的输入字段（使用 HttpPost）。

对于简单的输入字段，只需return View(model)。对于SelectList，您需要重新设置值。

这是一个简单的演示，如下所示：

型号：

public class Test
{
    public int Id { get; set; }
    public string Name { get; set; }
    public Category Category { get; set; }
}
public class Category
{
    public int Id { get; set; }
    public string CName { get; set; }
}

查看：

@model Test
<h1>Edit</h1>

<h4>Test</h4>
<hr />
<div class="row">
    <div class="col-md-4">
        <form asp-action="Edit">
            <div asp-validation-summary="ModelOnly" class="text-danger"></div>
            <input type="hidden" asp-for="Id" />
            <div class="form-group">
                <label asp-for="Name" class="control-label"></label>
                <input asp-for="Name" class="form-control" />
                <span asp-validation-for="Name" class="text-danger"></span>
            </div>
            <div>
                <label asp-for="Category"></label>
                <select asp-for="Category.Id" asp-items="@ViewBag.Category"></select>
                <span asp-validation-for="Category.Id" class="text-danger"></span>
            </div>
            <div class="form-group">
                <input type="submit" value="Save" class="btn btn-primary" />
            </div>
        </form>
    </div>
</div>

<div>
    <a asp-action="Index">Back to List</a>
</div>

@section Scripts {
    @{await Html.RenderPartialAsync("_ValidationScriptsPartial");}
}

控制器：

public class TestsController : Controller
{
    private readonly YourDbContext _context;
    private readonly List<Category> categories;
    public TestsController(YourDbContext context)
    {
        _context = context;
        categories = _context.Category.ToList();
    }
    // GET: Tests/Edit/5
    public async Task<IActionResult> Edit(int? id)
    {
        var test = await _context.Test.FindAsync(id);
        ViewBag.Category = new SelectList(categories, "Id", "CName", test.Category.Id);
        if (test == null)
        {
            return NotFound();
        }
        return View(test);
    }

    // POST: Tests/Edit/5
    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<IActionResult> Edit(int id, Test test)
    {
        //do your stuff...
        //...
        //repopulate the selectlist
        ViewBag.Category = new SelectList(categories, "Id", "CName", test.Category.Id);
        return View(test);
    }
}

结果：

更新：

Home.cshtml：

@model BookModel

<form method="post" asp-controller="Home" asp-action="Home" role="post">
    <div class="form-group">
        <label asp-for="bookName"></label>
        <select name="bookName" asp-items="@ViewBag.message">
        </select>
    </div>
    <div class="form-group">
        <label asp-for="Author"></label>
        <input asp-for="Author" class="form-control" />
    </div>
    <div class="form-group">
        <input type="submit" value="Submit" class="btn btn-primary" />
    </div>
</form>

家庭控制器：

public IActionResult Home()
{
    GetBooksDDL();
    return View();
}
public void GetBooksDDL(string bookname = "")
{
    List<BookModel> bookName = new List<BookModel>();
    //for easy testing,I just manually set the value
    bookName = new List<BookModel>() {
        new BookModel(){  ID=1, bookName="aaa",Author="aaa"},
        new BookModel(){  ID=2, bookName="bbb",Author="bbb"},
        new BookModel(){  ID=3, bookName="ccc",Author="ccc"}
    };
    bookName.Insert(0, new BookModel { ID = 0, bookName = "" });
    ViewBag.message = new SelectList(bookName, "ID", "bookName", bookname);
}

[HttpPost("[action]")]
[Produces("application/json")]
public async Task<IActionResult> Home(BookModel bookModel)
{            
        //do all the submit actions
        //after all of the actions are complete return the view:
        GetBooksDDL(bookModel.bookName);
        return View(bookModel);
        
}

结果：