ASP.Net MVC：如何动态地向任何模型属性添加验证(ASP.Net MVC: How to add validation to any model property on the fly)

 我很高兴知道如何在运行时向我的模型的任何属性添加验证而不触及代码。 所以寻找指南如何在asp.net mvc中实现我的目标。 
 
 样本模型属性 
 
[Required(ErrorMessage = "The field {0} is required")]
[Display(Name = "Company")]
public string Name { get; set; }
 
 上面的代码是一个示例，其中在编码时添加了验证，但我不想在编码时附加验证，而我想在运行时以这样的方式编码，我将能够向任何模型注入验证属性。 
 
 我搜索谷歌并找到一个样本，但不明白如何使用它来完成我的任务。 这是我找到的示例代码，但不清楚如何将它用于我的目的。 
 
 在模型中： 
 
[Domainabcd(20, "Bar", "Baz", ErrorMessage = "The combined minimum length of the Foo, Bar and Baz properties should be longer than 20")]
public string strAccessionId { get; set; }
 
 在DomainabcdAttribute.cs中： 
 
public class DomainabcdAttribute : ValidationAttribute, IClientValidatable
 //Domain is the Attribute name 
//if you do not inherit IClientValidatable ,the server validation still will work ,but the Client validation will not work.

    {
        public DomainAttribute(int minLength, params string[] propertyNames) 
// this is where to get parameters from you pass 
//such as : 20, "Bar", "Baz",
        {
            this.PropertyNames = propertyNames;
            this.MinLength = minLength;
        }

        public string[] PropertyNames { get; private set; }
        public int MinLength { get; private set; }

        protected override ValidationResult IsValid(object value, ValidationContext validationContext)
        {
           ///this is where to decide if to display error ,or not.
            //var properties = this.PropertyNames.Select(validationContext.ObjectType.GetProperty);
            //var values = properties.Select(p => p.GetValue(validationContext.ObjectInstance, null)).OfType<string>();
            //var totalLength = values.Sum(x => x.Length) + Convert.ToString(value).Length;
            //if (totalLength < this.MinLength)
            //{
               //this is the place to return the validation result
             //so you may just use this line code:   return new ValidationResult(validationContext.DisplayName)
                return new ValidationResult(this.FormatErrorMessage(validationContext.DisplayName));
            //}
            //return null; //no error massage

       }
        //this is for Client to display error message 
        public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
        {
            var modelClientValidationRule = new ModelClientValidationRule
            {
                ValidationType = "requiredif",
                ErrorMessage = ErrorMessage //Added ,pass the error message 

            };

            modelClientValidationRule.ValidationParameters.Add("param", this.PropertyNames); //Added
            return new List<ModelClientValidationRule> { modelClientValidationRule };

        }
        // public override string FormatErrorMessage(string name) //to custom format for error message
        //{
        //    string[] values = this.Values.Select(value => string.Format("'{0}'", value)).ToArray();
        //     //return string.Format("{0}{1}", name, string.Join(",", values));
        //     return string.Format(base.ErrorMessageString, name, string.Join(",", values));
        // }
    }
 
 我的目标如下 
 
 1）假设第一天我将在运行时向name属性添加验证，如名称应该是必需的 
 
 2）几天后我会在名称属性中添加另一个验证，假设名称不应该有像@ , : # etc特殊字符。 
 
 3）几天之后我会再次向名称属性添加另一个验证，假设名称的长度不应小于10个字符。 
 
 希望我清楚我想要实现的目标。 所以，任何做过它的人都只是帮我提供示例代码。 
 
 谢谢 

i am curios to know how could i add validation to any property of my model at run time without touching the code. so looking for guide line how to achieve what i am after in asp.net mvc.
 
sample model property
 
[Required(ErrorMessage = "The field {0} is required")]
[Display(Name = "Company")]
public string Name { get; set; }
 
the above code is a sample where validation has been added when coding but i do not want to attach validation at coding time rather i want to code in such a way as a result at the run time i will be able to inject validation to any model property.
 
i search a google and found a sample but do not understand how to use it to achieve my task. here is a sample code what i found but not clear how to use it for my purpose.
 
in Model:
 
[Domainabcd(20, "Bar", "Baz", ErrorMessage = "The combined minimum length of the Foo, Bar and Baz properties should be longer than 20")]
public string strAccessionId { get; set; }
 
in DomainabcdAttribute.cs:
 
public class DomainabcdAttribute : ValidationAttribute, IClientValidatable
 //Domain is the Attribute name 
//if you do not inherit IClientValidatable ,the server validation still will work ,but the Client validation will not work.

    {
        public DomainAttribute(int minLength, params string[] propertyNames) 
// this is where to get parameters from you pass 
//such as : 20, "Bar", "Baz",
        {
            this.PropertyNames = propertyNames;
            this.MinLength = minLength;
        }

        public string[] PropertyNames { get; private set; }
        public int MinLength { get; private set; }

        protected override ValidationResult IsValid(object value, ValidationContext validationContext)
        {
           ///this is where to decide if to display error ,or not.
            //var properties = this.PropertyNames.Select(validationContext.ObjectType.GetProperty);
            //var values = properties.Select(p => p.GetValue(validationContext.ObjectInstance, null)).OfType<string>();
            //var totalLength = values.Sum(x => x.Length) + Convert.ToString(value).Length;
            //if (totalLength < this.MinLength)
            //{
               //this is the place to return the validation result
             //so you may just use this line code:   return new ValidationResult(validationContext.DisplayName)
                return new ValidationResult(this.FormatErrorMessage(validationContext.DisplayName));
            //}
            //return null; //no error massage

       }
        //this is for Client to display error message 
        public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
        {
            var modelClientValidationRule = new ModelClientValidationRule
            {
                ValidationType = "requiredif",
                ErrorMessage = ErrorMessage //Added ,pass the error message 

            };

            modelClientValidationRule.ValidationParameters.Add("param", this.PropertyNames); //Added
            return new List<ModelClientValidationRule> { modelClientValidationRule };

        }
        // public override string FormatErrorMessage(string name) //to custom format for error message
        //{
        //    string[] values = this.Values.Select(value => string.Format("'{0}'", value)).ToArray();
        //     //return string.Format("{0}{1}", name, string.Join(",", values));
        //     return string.Format(base.ErrorMessageString, name, string.Join(",", values));
        // }
    }
 
my objective as follows
 
1) suppose first day i will add validation to name property at run time like name should be required
 
2) after few days i will add another validation to name property on the fly suppose name should not have special character like @ , : # etc.
 
3) again after few days i will add another validation to name property on the fly suppose name's length should not be less than 10 character.
 
hope i am clear what i am trying to achieve. so please anyone who did it just help me with sample code.
 
thanks

原文：https://stackoverflow.com/questions/42714701