C#在List< string>上设置数据注释 [英] C# Set Data Annotation on List<string>

问题描述

我有这段代码:

[Required]
public List<string> myStringList { get; set; }

不幸的是，它不起作用，验证程序完全忽略了它.

Unfortunatelly, it doesn't work, tha validator totally ignores it.

此外，它可以正常工作:

Besides, this works fine:

[Required]
public string myString { get; set; }

和DateTimes也可以正常工作.显然，问题不在于我的验证器，而在于注释.所以问题是，我应该如何在列表上设置数据注释?

and DateTimes work fine as well. Obviously, the problem doesn't lie on my validator, but on the annotation. So the question is, how should I set the Data Annotation on my list ?

推荐答案

创建自己的数据注释属性，例如:

Create your own data annotation attribute, crude example:

public class ListHasElements : ValidationAttribute
{
   public override bool IsValid(List mylist)
   {
      if(mylist == null)
         return false;

      return mylist.Any();   
   }
}

然后像这样使用它:

[ListHasElements(ErrorMessage = "List must contain an element")]
public List<string> myStringList { get; set; }

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