验证上下文总是NULL？ [英] Validation Context is always NULL?

问题描述

我有自定义的验证属性像这样的：

I have custom validation attribute such as this:

    public class MyCustomAttribute : ValidationAttribute {
    protected override ValidationResult IsValid(object value, ValidationContext validationContext) {
        if ((int)value == 100) {
            // do some checking to validate & return ValidationResult accordingly

        } else return ValidationResult.Success;
    }
}

在这样的用法：

    [DisplayName("My Custom Property")]
    [MyCustom(ErrorMessage = "ERROR!!!")]
    public int? MyCustomProperty { get; set; }

我的问题是：为什么是这里面MyCustomAttribute，该IsValid的方法中，validationContext始终是NULL ？有没有什么特别的，我需要设置得到它不为NULL？

My question is: why is it that inside MyCustomAttribute, within the IsValid method, validationContext is always NULL? Is there anything special I need to set to get it not to be NULL?

推荐答案

如果您使用

ValidationResult IsValid(object value, ValidationContext validationContext)

要检查，如果数据是有效的，你必须用

to check if data is valid you have to use

v.GetValidationResult(propertyValue,new ValidationContext(this))!= ValidationResult.Success

而不是

 v.IsValid(propertyValue)

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