C# 利用特性（Attribute）实现自定义验证

// 自定义必填特性
[AttributeUsage(AttributeTargets.Property)]
public class RequiredAttribute : Attribute { }
// 数据验证工具
public class DataValidator
{
    public static bool Validate(object obj, out List<string> errors)
    {
        errors = new List<string>();
        var properties = obj.GetType().GetProperties();
        foreach (var prop in properties)
        {
            var requiredAttr = prop.GetCustomAttribute<RequiredAttribute>();
            if (requiredAttr != null)
            {
                var value = prop.GetValue(obj);
                if (value == null || string.IsNullOrEmpty(value.ToString()))
                {
                    errors.Add($"{prop.Name} 为必填项");
                }
            }
        }
        return errors.Count == 0;
    }
}
// 测试实体
public class User
{
    [Required]
    public string Name { get; set; }
    public int Age { get; set; }
}
// 调用示例
public static void TestAttribute()
{
    var user = new User { Age = 25 };
    if (!DataValidator.Validate(user, out var errors))
    {
        foreach (var err in errors) Console.WriteLine(err);
    }
}