C# ValidationAttribute required when
public class RequiredIfAttribute : ValidationAttribute, IClientValidatable
{
private String PropertyName { get; set; }
private Object DesiredValue { get; set; }
private readonly RequiredAttribute _innerAttribute;
public RequiredIfAttribute(String propertyName, Object desiredvalue)
{
PropertyName = propertyName;
DesiredValue = desiredvalue;
_innerAttribute = new RequiredAttribute();
}
protected override ValidationResult IsValid(object value, ValidationContext context)
{
var dependentValue = context.ObjectInstance.GetType().GetProperty(PropertyName).GetValue(context.ObjectInstance, null);
if (dependentValue.ToString() == DesiredValue.ToString())
{
if (!_innerAttribute.IsValid(value))
{
return new ValidationResult(FormatErrorMessage(context.DisplayName), new[] { context.MemberName });
}
}
return ValidationResult.Success;
}
public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
{
var rule = new ModelClientValidationRule
{
ErrorMessage = ErrorMessageString,
ValidationType = "requiredif",
};
rule.ValidationParameters["dependentproperty"] = (context as ViewContext).ViewData.TemplateInfo.GetFullHtmlFieldId(PropertyName);
rule.ValidationParameters["desiredvalue"] = DesiredValue is bool ? DesiredValue.ToString().ToLower() : DesiredValue;
yield return rule;
}
}