c# - 具有空值的必需字符串属性在 ASP.NET Core 2 Razor 页面中给出 IsValid=true

Question

我真的很困惑。我在 ASP.NET Core 2 上有一个 Razor 页面，它有一个名为 SchemaId 的必需属性。我尝试将其标记为 [Required]、[BindRequired] 和 [Required(AllowEmptyStrings = false)]，但当我发布时在我的表单中，我看到 SchemaId 是 null 而 ModelState.IsValid == true。这是 Upload.cshtml.cs:

namespace Uploader.Pages
{
    public class UploadModel : PageModel
    {
        private IUploader _uploader;

        public UploadModel(IUploader uploader)
        {
            _uploader = uploader;
        }

        [BindProperty]
        public IEnumerable<IFormFile> UploadedFiles { get; set; }

        [Required(AllowEmptyStrings = false)]
        [BindProperty]
        [BindRequired]
        public string SchemaId { get; set; }


        public void OnGet(string schemaId = null)
        {
            SchemaId = schemaId;
        }

        public async Task<IActionResult> OnPostAsync()
        {
            // SchemaId is NULL right here!
            if (!ModelState.IsValid) // Yet IsValid = true!
            {
                return Page();
            }

            // Use _uploader to actually upload the file

            return RedirectToPage("/Next", new { uploadId = uploadId, schemaId = SchemaId });
        }
    }
}

Upload.cshtml 文件的相关摘录:

<div asp-validation-summary="All"></div>
<form enctype="multipart/form-data" method="POST" asp-page="Upload">
    <input class="inputfile" type="file" id="UploadedFiles" multiple="multiple" name="UploadedFiles">
    <label for="UploadedFiles">
        <span>Choose a file...</span>
    </label>
    <input type="hidden" asp-for="SchemaId">
    <button type="submit" class="inputfilesubmit">Upload</button>
</form>

如何让模型验证正常工作？

Answer 1

我想我找到了原因。

在 PageModel 中定义的

[BindRequired] 和 [Required] 属性似乎被忽略了。因此，您需要像下面这样验证模型:

public class Schema
{
    [Required]
    [BindRequired]
    public string Id { get; set; }
}
public class TestModel : PageModel
{
    [BindProperty]
    public Schema Schema { get; set; }

    public async Task<IActionResult> OnPostAsync()
    {
        // SchemaId is NULL right here!
        if (!ModelState.IsValid) // Yet IsValid = true!
        {
            return Page();
        }

        return Page();
    }

}

然后在cshtml中

<div asp-validation-summary="All"></div>
<form enctype="multipart/form-data" method="POST" asp-page="Upload">
    <input class="inputfile" type="file" id="UploadedFiles" multiple="multiple" name="UploadedFiles">
    <label for="UploadedFiles">
        <span>Choose a file...</span>
    </label>
    <input type="hidden" asp-for="Schema.Id">
    <button type="submit" class="inputfilesubmit">Upload</button>
</form>

我还没有找到任何提到这个的文档，但是在 Microsoft documentation 中他们还在单独的类中编写验证属性，所以我认为这种行为是意料之中的。

希望这能解决问题。