[英]Error: System.InvalidCastException: Unable to cast object of type 'System.Byte' to type 'System.Int32'
[英]Entity Framework | Error: InvalidCastException: The field of type System.Int32 must be a string, array or ICollection type
当我向我的 Home Controller提交(或发布)一个名为 NewsletterSignup 的方法的请求时,我收到以下错误。 在我的时事通讯表单提交后以及在调用此方法并创建捕获表单数据的 object 之前提示错误,从而造成难以排除故障的情况,并确定此确切问题正在传播的位置。
错误
处理请求时发生未处理的异常。
InvalidCastException : System.Int32 类型的字段必须是字符串、数组或 ICollection 类型。 ... System.ComponentModel.DataAnnotations.MaxLengthAttribute.IsValid(对象值)
... System.ComponentModel.DataAnnotations.ValidationAttribute.IsValid(对象值,ValidationContext 验证上下文)
... System.ComponentModel.DataAnnotations.ValidationAttribute.GetValidationResult(对象值,ValidationContext 验证上下文)
AppDbContext.cs
应用程序数据库上下文
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; }
}
}
集合模型.cs
查看 index.cshtml 和共享 newsletter.cshtml 视图上使用的 Model
namespace KingsEye.Models
{
public class CollectionModel
{
public Home Home { get; set; }
public Pages Pages { get; set; }
public Newsletter Newsletter { get; set; }
}
}
时事通讯.cs
时事通讯查看 Model
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
}
}
家庭控制器.cs
主页 Controller
[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>
想要确定此错误从何处传播,以便可以相应地调试有问题的异常。 任何建议或方向肯定会受到赞赏。
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。
Maxlengh 属性在您的代码中造成问题。您在发布、删除或获取时可能不会遇到任何问题,但在更新或编辑时会弹出错误。只需摆脱该属性添加迁移和更新数据库。
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