gistfile1.cs

    public class GrandFather
    {
        [StringLength(5, MinimumLength = 3)]
        public string Name { get; set; }

        [NestedValidation]
        public List<Father> Fathers { get; set; }
    }
    
    public class Father
    {
        [Range(1, 130)]
        public int Age { get; set; }

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

        [NestedValidation]
        public IEnumerable<Son> Sons { get; set; }
    }
    
    public class Son : IValidatableObject
    {
        [Range(1, 130)]
        public int Age { get; set; }

        [Required(AllowEmptyStrings = false)]
        public string Name { get; set; }

        public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
        {
            var result = new List<ValidationResult>();

            if (this.Age % 2 == 0)
            {
                var memberNames = new List<string> { "Age" };
                result.Add(new ValidationResult("Age不得為偶數", memberNames));
            }

            return result;
        }
    }

gistfile2.cs

        [TestMethod]
        public void 驗證GrandFather()
        {
            var grandFather = new GrandFather
            {
                Name = "hi",
                Fathers = new List<Father>
                {
                    new Father
                    {
                        Name= "Father1",
                        Age=81,
                        Sons = new List<Son>
                        {
                            new Son{Name="91", Age=300},
                            new Son{Name = "92", Age= 11},
                            new Son{Name = "93", Age= 202},
                        }
                    },
                    new Father
                    {
                        Age=82,
                        Sons = new List<Son>
                        {
                            new Son{Name="F2_1", Age=-1},
                            new Son{Name = "F2_2", Age= -2},
                            new Son{Name = "F2_3", Age= 4},
                        }
                    },
                }
            };

            var validator = new DataAnnotationValidator();

            var isValid = validator.TryValidate(grandFather);

            Assert.AreEqual(false, isValid);

            Assert.AreEqual(7, validator.ValidationResults.Count);
        }

gistfile3.txt

ValidationResults:

+  	[0]	{欄位 Name 必須是最小長度為 3 且最大長度為 5 的字串。}	System.ComponentModel.DataAnnotations.ValidationResult
+		[1]	{欄位 Fathers[0].Sons[0].Age 必須介於 1 到 130 之間。}	System.ComponentModel.DataAnnotations.ValidationResult
+		[2]	{欄位 Fathers[0].Sons[2].Age 必須介於 1 到 130 之間。}	System.ComponentModel.DataAnnotations.ValidationResult
+		[3]	{Fathers[1].Name 欄位是必要項。}	System.ComponentModel.DataAnnotations.ValidationResult
+		[4]	{欄位 Fathers[1].Sons[0].Age 必須介於 1 到 130 之間。}	System.ComponentModel.DataAnnotations.ValidationResult
+		[5]	{欄位 Fathers[1].Sons[1].Age 必須介於 1 到 130 之間。}	System.ComponentModel.DataAnnotations.ValidationResult
+		[6]	{Fathers[1].Sons[2].Age不得為偶數}	System.ComponentModel.DataAnnotations.ValidationResult