.NET Core MVC 中的可选模型属性绑定 [英] Optional Model Properties Binding in .NET Core MVC

问题描述

我创建了一个具有以下属性的 AccountModel

I have created one AccountModel which has following properties

public class AccountModel
{
    [Required]
    [EmailAddress]
    public string Email { get; set; }

    [Required]
    [StringLength(10, MinimumLength = 6)]
    public string Password { get; set; }

    [NotMapped] // Does not effect with your database
    [Compare("Password")]
    [BindRequired]
    public string ConfirmPassword { get; set; }
}

我正在尝试对 SignUp 和 SignIn 使用相同的模型.这个模型非常适合注册，但是当我为 SignIn 使用相同的模型时，我的模型变得无效.

I am trying to use same model for SignUp and SignIn. This model is perfectly working for signup but when I am using same model for SignIn my model becomes Invalid.

我知道原因，因为我没有为 Confirm Password 属性传递值.我尝试了以下

I know the reason because, I am not passing value for Confirm Password property. I tried following

1. 我使用?"创建了 NULLABLE但它给了我警告(见附件截图)

1. I made NULLABLE by using "?" bu it is giving me warning (See attached screenshot)

我也试过 [BindRequired] 注释，它也不起作用.

I have also tried [BindRequired] annotation which is also not working.

我正在使用 ASP.NET Core 3.1 并尝试使用单一模型进行登录和注册.

I am using ASP.NET Core 3.1 and trying to use single Model for both login and signup.

有什么解决办法吗?我正在学习 .NET Core &MVC 所以对这个主题的了解较少.

Is there any solution for that? I am learning .NET Core & MVC so having less knowledge about this subject.

提前感谢您的帮助.

推荐答案

这被称为 Nullable contexts，基于其 文档:

This is called Nullable contexts, based on its documentation:

可空上下文可以对编译器如何解释引用类型变量进行细粒度控制.任何给定源代码行的可为空的注释上下文要么启用要么禁用.您可以将 C# 8.0 之前的编译器视为在禁用的可为空上下文中编译所有代码:任何引用类型都可能为空.也可以启用或禁用可为空警告上下文.可为空的警告上下文指定编译器使用其流分析生成的警告.

Nullable contexts enable fine-grained control for how the compiler interprets reference type variables. The nullable annotation context of any given source line is either enabled or disabled. You can think of the pre-C# 8.0 compiler as compiling all your code in a disabled nullable context: any reference type may be null. The nullable warnings context may also be enabled or disabled. The nullable warnings context specifies the warnings generated by the compiler using its flow analysis.

你可以像这样摆脱这个警告:

You can get rid of this warning like this:

#nullable enable
    public string? ConfirmPassword { get; set; }
#nullable disable

作为另一种解决方法，如果您想始终摆脱项目中的此警告，您可以在 .csproj 文件中添加 Nullable 元素.右键单击您的项目并单击编辑项目文件"，然后将 Nullable 元素添加到您的 PropertyGroup 部分，如下所示:

As another workaround, if you want to always get rid of this warning in your project, you can add the Nullable element in your .csproj file. Right click on your project and click "Edit Project File", then add the Nullable element to your PropertyGroup section, just like the following:

<PropertyGroup>
    <TargetFramework>netcoreapp3.1</TargetFramework>
    <Nullable>enable</Nullable>
</PropertyGroup>

您只需要重新构建您的项目一次即可查看结果.

You just need to Re-Build your project once to see the result.

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