ASP.NET MVC-将模型值传递给数据注释参数 [英] ASP.NET MVC - Pass model value to data annotation parameter

问题描述

我想将模型中的一个属性值传递给数据注释以验证密码属性，但是我不知道如何实现此目的.以这种方式执行此操作时，出现以下错误:

I want to pass a value from one of my properties in my model to my data annotation to validate my password property, but I have no idea how I can achieve this. When I am doing this at this way I get the following error:

an attribute argument must be a constant expression typeof expression or array

我的模特:

public class LoginModel
{
    public string Voornaam { get; set; }
    public string Achternaam { get; set; }
    public string Gebruikersnaam { get; set; }

    [Password(AttributeVoornaam = this.Voornaam, AttributeAchternaam = this.Achternaam, AttributeGebruikersnaam = this.Gebruikersnaam)]
    public string Wachtwoord { get; set; }
}

在我的数据注释中，我正在这样做:

And in my data annotation I am doing this:

public class PasswordAttribute : ValidationAttribute
{
    public string AttributeVoornaam { get; set; }
    public string AttributeAchternaam { get; set; }
    public string AttributeGebruikersnaam { get; set; }

    public override bool IsValid(object value)
    {
        string strValue = value.ToString();

        if (strValue.Contains(AttributeVoornaam.ToLower()) || strValue.Contains(AttributeAchternaam.ToLower()) ||
               strValue.Contains(AttributeGebruikersnaam.ToLower()))
        {
            ErrorMessage = "Uw wachtwoord mag niet uw voornaam, achternaam of gebruikersnaam bevatten.";
            return false;
        }
        else
        {
            return true;
        }
    }
}

推荐答案

您不能将变量值(在编译时未评估的值)传递到属性中.它们必须是文字值或常量值.

You can't pass variable values (values that are not evaluated at compile-time) into attributes. They have to be literal values or constant values.

可以传递给属性的是您要在运行时评估的模型属性的名称，然后让您的IsValid方法在以下位置评估这些值通过访问覆盖中的ValidationContext并返回ValidationAttribute的ValidationResult来运行时.

What you can pass into attributes, though, are the names of the properties of your model that you want to evaluate at run-time, and then have your IsValid method evaluate these values at run-time by accessing the ValidationContext in the override that returns a ValidationResult of ValidationAttribute.

或者，如果您始终在评估这些相同的属性，则只需获取对模型的引用，然后直接使用它即可:

Or, if you are always evaluating these same properties, then you can just grab the reference to your model, and use that directly:

protected override ValidationResult IsValid(object value, ValidationContext validationContext)
{
    LoginModel loginModel = (LoginModel)validationContext.ObjectInstance;

    string strValue = value.ToString();

    if (strValue.Contains(loginModel.Voornaam.ToLower()) || 
        strValue.Contains(loginModel.Achternaam.ToLower()) ||             
        strValue.Contains(loginModel.Gebruikersnaam.ToLower()))
    {
        ErrorMessage = "Uw wachtwoord mag niet uw voornaam, achternaam of gebruikersnaam bevatten.";
        return false;
    }
    else
    {
        return true;
    }
}

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