从ClientModelValidationContext访问完整的html字段属性

问题描述

我有一个自定义验证属性，我正在从asp.net转移到asn.net-core.这是实现IClientModelValidator的一个简单的requiredif属性；

I have a custom validation attribute that i'm moving across from asp.net to asn.net-core. It's a simple requiredif attribute implementing IClientModelValidator;

public class RequiredIfAttribute : ValidationAttribute, IClientModelValidator
    {
        private String PropertyName { get; set; }
        private Object DesiredValue { get; set; }

        private readonly RequiredAttribute _innerAttribute;

        public RequiredIfAttribute(String propertyName, Object desiredvalue)
        {
            PropertyName = propertyName;
            DesiredValue = desiredvalue;
            _innerAttribute = new RequiredAttribute();
        }

        protected override ValidationResult IsValid(object value, ValidationContext context)
        {
            var dependentValue = context.ObjectInstance.GetType().GetProperty(PropertyName).GetValue(context.ObjectInstance, null);

            if (dependentValue.ToString() == DesiredValue.ToString())
            {
                if (!_innerAttribute.IsValid(value))
                {
                    return new ValidationResult(FormatErrorMessage(context.DisplayName), new[] { context.MemberName });
                }
            }
            return ValidationResult.Success;
        }

        public void AddValidation(ClientModelValidationContext context)
        {
            context.Attributes.Add("data-val", "true");
            context.Attributes.Add("data-val-requiredif", ErrorMessage);

            //this following line is the issue
            context.Attributes.Add("data-val-requiredif-dependentproperty", (context as ViewContext).ViewData.TemplateInfo.GetFullHtmlFieldId(PropertyName));
            context.Attributes.Add("data-val-requiredif-desiredvalue", DesiredValue.ToString());

        }
    }

正如我在AddValidation方法内的代码行上方注释过的那样，我似乎无法通过将上下文转换为ViewContext并以这种方式访问​​其名称来获得完整的html字段ID，就像我以前在asp.net中使用的那样.

As i've commented above the line within the AddValidation method, I can't seem to get the full html field id like I used to in asp.net by casting the context to a ViewContext and accessing it's name that way.

获取不是当前上下文的属性的完整html字段ID的新方法是什么?

What is the new way of getting the full html field id of a property that's not the current context?

例如旧代码；

(context as ViewContext).ViewData.TemplateInfo.GetFullHtmlFieldId(PropertyName)

可能已返回诸如"viewModel.ComplexObject.PropertyID"之类的路径.

Might have returned a path such as "viewModel.ComplexObject.PropertyID".

我尝试在上下文的ModelMetaData.ContainerContext中查找，但是我不能保证属性容器包含我需要的属性(可以嵌套在其中的其他位置).

I've tried looking in the context's ModelMetaData.ContainerContext But I can't guarantee that the properties container contains the property I need (it could be nested elsewhere within that).

例如，假设我的模型看起来像这样；

For example, let's assume that my model looks like so;

 public class A
    {
        [RequiredIf("PropertyB", true)]
        public string propertyA { get; set; }

        public bool PropertyB { get; set; }
    }

有什么想法吗?

推荐答案

在 AddValidation 方法中使用以下代码:

Use following code in AddValidation method:

var viewContext = context.ActionContext as ViewContext viewContext;

var fullName = viewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(PropertyName);

var fullId = propertyFullName.Replace(".", "_");

注意:TemplateInfo现在在asp.net核心中没有 GetFullHtmlFieldId 方法

Note: TemplateInfo now not have GetFullHtmlFieldId Method in asp.net core

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