[英]How to get property name by one of it's attributes' value using reflection or how to get property info of data property which is currently validating?
我想编写自定义验证属性并添加具有验证错误的其他成员名称到验证结果。 问题是我想根据属性名称和无效匹配属性索引或键动态生成成员名称(我想验证IEnumerables或IDictionaries),如Names[0]
, Names[1]
, Names[key]
等。例如:
模型:
public class ModelClass
{
[ItemMaxLength(10)]
[Display(ResourceType = typeof(CategoriesRename), Name = "CategoryNamesFieldName")]
public IDictionary<string, string> Names { get; set; }
}
属性:
public class ItemMaxLengthAttribute : ValidationAttribute
{
private readonly int _maxLength = int.MaxValue;
public ItemMaxLengthAttribute(int maxLength)
{
_maxLength = maxLength;
}
protected override ValidationResult IsValid(object value, ValidationContext validationContext)
{
...
// I can get instance and it's type from validation context
var instance = validationContext.ObjectInstance; // which is instance of ModelClass
var instanceType = validationContext.ObjectType; //which is typeof(ModelClass)
var dispayName = validationContext.DisplayName; //which is value of Display attribute
...
}
}
所以主要的想法是(我不喜欢它)以获取当前属性的DysplayName
属性值( dispayName
)。 我有点被困在这里一段时间了。 也许是否有其他方法来获取正在验证的属性的属性信息?
PS我已经尝试过MemberName
属性,正如Alexandre Rondeau所说,但问题是validationContext.MemberName = null
因此无法使用。 MSDN也说这个属性代表一个实体成员名,而不是相应数据字段 的名称,我需要相应数据字段 的名称 。
使用该代码,两个测试传递,因此MemberName不为null。
[TestClass]
public class RefectionInValidationTest
{
[TestMethod]
public void GivenAModelWithItemMaxAttributeOnFieldName_WhenValidating_ThenModelClassIsValid()
{
//Arange
var validModelClass = new ModelClass();
var validations = new Collection<ValidationResult>();
//Act
var isValid = Validator.TryValidateObject(validModelClass, new ValidationContext(validModelClass, null, null), validations, true);
//Assert
Assert.IsTrue(isValid);
}
[TestMethod]
public void GivenAModelWithItemMaxAttributeOnFieldNotName_WhenValidating_ThenModelClassIsInvalid()
{
//Arange
var invalidaModelClass = new InvalidModelClass();
var validations = new Collection<ValidationResult>();
//Act
var isValid = Validator.TryValidateObject(invalidaModelClass, new ValidationContext(invalidaModelClass, null, null), validations, true);
//Assert
Assert.IsFalse(isValid);
}
}
public class ModelClass
{
[ItemMaxLength(10)]
public IDictionary<string, string> Names { get; set; }
}
public class InvalidModelClass
{
[ItemMaxLength(10)]
public IDictionary<string, string> NotNames { get; set; }
}
public class ItemMaxLengthAttribute : ValidationAttribute
{
private readonly int _maxLength = int.MaxValue;
public ItemMaxLengthAttribute(int maxLength)
{
_maxLength = maxLength;
}
protected override ValidationResult IsValid(object value, ValidationContext validationContext)
{
var propretyInfo = validationContext.ObjectType.GetProperty(validationContext.MemberName);
if (propretyInfo.Name == "Names")
return ValidationResult.Success;
return new ValidationResult("The property isn't 'Names'");
}
}
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