InvalidCastException: System.Int32类型的字段必须是字符串、数组或ICollection类型
InvalidCastException: System.Int32类型的字段必须是字符串、数组或ICollection类型
提问于 2019-10-20 20:02:44
问题
当我向我的主控制器( Home )提交(或发布)一个名为NewsletterSignup的方法请求时，我收到了以下错误。此错误是在我的新闻稿表单提交后，以及在何时调用此方法和创建捕获表单数据的对象之前提示的，这会造成很难排除故障的情况，并确定此问题在何处传播。
错误
处理请求时发生了未处理的异常。
InvalidCastException：类型System.Int32的字段必须是字符串、数组或ICollection类型。..。System.ComponentModel.DataAnnotations.MaxLengthAttribute.IsValid(object值)
..。System.ComponentModel.DataAnnotations.ValidationAttribute.IsValid(object值，ValidationContext validationContext)
..。System.ComponentModel.DataAnnotations.ValidationAttribute.GetValidationResult(object值，ValidationContext validationContext)
文件
AppDbContext.cs
应用数据库上下文
namespace KingsEye.Data
{
public class AppDbContext : IdentityDbContext
{
public AppDbContext(DbContextOptions<AppDbContext> options) : base(options) { }
public DbSet<Home> Home { get; set; }
public DbSet<Pages> Pages { get; set; }
public DbSet<Newsletter> Newsletter { get; set; }
}
}CollectionModel.cs
用于index.cshtml和共享newsletter.cshtml视图的视图模型
namespace KingsEye.Models
{
public class CollectionModel
{
public Home Home { get; set; }
public Pages Pages { get; set; }
public Newsletter Newsletter { get; set; }
}
}Newsletter.cs
时事通讯视图模型
namespace KingsEye.Models
{
public class Newsletter
{
#region Newsletter
[Display(Name = "Newsletter ID: ")]
[Required(ErrorMessage = "Newsletter ID Required!")]
public int Id { get; set; }
[Display(Name = "Full Name: ")]
[DataType(DataType.Text)]
public string Fname { get; set; }
[Display(Name = "E-Mail Address: ")]
[DataType(DataType.EmailAddress)]
public string Email { get; set; }
[Display(Name = "Phone Number: ")]
[DataType(DataType.PhoneNumber)]
public int Phone { get; set; }
[Display(Name = "Active: ")]
[MaxLength(1)]
public int Active { get; set; }
[Display(Name = "GUID: ")]
[MaxLength(37)]
public string GUID { get; set; }
[Display(Name = "Created: ")]
[DataType(DataType.DateTime)]
public DateTime Create { get; set; }
[Display(Name = "Updated: ")]
[DataType(DataType.DateTime)]
public DateTime Update { get; set; }
#endregion
}
}HomeController.cs
家庭控制器
[HttpPost]
public async Task<IActionResult> NewsletterSignup(CollectionModel model)
{
<= Error: is prompting prior to the body of this method being called,
and the parameter object being populated with post data!!!
var newsletter = new Newsletter
{
Id = 0,
Fname = model.Newsletter.Fname,
Email = model.Newsletter.Email,
Phone = model.Newsletter.Phone,
Active = 0,
GUID = Guid.NewGuid().ToString(),
Create = DateTime.Now,
Update = DateTime.Now
};
...
}_Newsletter.cshtml
通讯表单的共享视图
@model CollectionModel
<div id="newsletter">
@if (User.Identity.IsAuthenticated)
{
<header>
<i class="far fa-envelope-open"></i>
<div class="text">Newsletter</div>
<i class="far fa-envelope-open"></i>
</header>
<main>Subscribe to our newsletter</main>
<footer>
<form asp-controller="Home" asp-action="NewsletterSignup" method="post" id="newsletter-form" class="text-danger input-form">
<div asp-validation-summary="ModelOnly"></div>
<div class="form-group">
<input asp-for="@Model.Newsletter.Id" type="hidden" value="0" />
</div>
<div class="form-group">
<input asp-for="@Model.Newsletter.Fname" id="email-signed" class="form-control" placeholder="Your Name" />
<span asp-validation-for="@Model.Newsletter.Fname"></span>
</div>
<div class="form-group">
<input asp-for="@Model.Newsletter.Email" type="hidden" value="place@holder.com" />
</div>
<div class="form-group">
<input asp-for="@Model.Newsletter.Phone" id="email-signed" class="form-control" placeholder="(000) 000-0000" />
<span asp-validation-for="@Model.Newsletter.Phone"></span>
</div>
<div class="form-group input-submit">
<input id="newsletter-subscribe" type="submit" value="Subscribe" class="btn material-button" />
</div>
<div class="form-group">
<input asp-for="@Model.Newsletter.Active" type="hidden" value="0" />
</div>
<div class="form-group">
<input asp-for="@Model.Newsletter.GUID" type="hidden" value="0" />
</div>
<div class="form-group">
<input asp-for="@Model.Newsletter.Create" type="hidden" value="0" />
</div>
<div class="form-group">
<input asp-for="@Model.Newsletter.Update" type="hidden" value="0" />
</div>
</form>
</footer>
}
else
{
<main>
Please <a asp-controller="Auth" asp-action="Register">Sign-Up</a> to Subscribe for a Newsletter!
</main>
}
</div>目标
希望确定此错误从何处传播，以便相应地调试所述异常。如有任何建议或指导，我们将不胜感激。
- ，谢谢并提前欢呼。
回答 2
Stack Overflow用户
发布于 2020-03-03 18:26:42
MaxLenght属性用于字符串
[Display(Name = "Active: ")]
[MaxLength(1)] // this will fail
public int Active { get; set; }
[Display(Name = "GUID: ")]
[MaxLength(37)] //this is okay
public string GUID { get; set; }获取数组或字符串数据的最大允许长度。
Stack Overflow用户
发布于 2022-07-11 05:07:10
Maxlengh属性在您的code.You中造成麻烦，在发布、删除或获取时可能不会遇到任何问题，但是当更新或编辑错误时，out.just会弹出该属性，添加迁移和更新数据库。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/58476819
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