实现IValidatableObject时的自定义错误消息

using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;

public class MyModel : IValidatableObject
{
    public string Name { get; set; }
    public int Age { get; set; }

    public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
    {
        if (string.IsNullOrEmpty(Name))
        {
            yield return new ValidationResult("姓名不能为空", new[] { nameof(Name) });
        }

        if (Age < 18)
        {
            yield return new ValidationResult("年龄必须大于等于18岁", new[] { nameof(Age) });
        }
    }
}

[HttpPost]
public IActionResult Create(MyModel model)
{
    if (ModelState.IsValid)
    {
        // 数据验证通过，执行相应的业务逻辑
        // ...
    }
    else
    {
        // 数据验证失败，处理错误消息
        foreach (var error in ModelState.Values.SelectMany(v => v.Errors))
        {
            // 处理错误消息
        }
    }
}