data-annotationsvalidationria

StringLengthAttribute doesn't seem to be working

Here is my Test class with data annotations:

class Test
{
  [Required, StringLength(10)]
  public string MyProperty { get; set; }
}

Here is my console test program:

class Program
{
  static void Main(string[] args)
  {
    var test = new Test {
      MyProperty = "this is way more than 10 characters and should fail."
    };

    var context = new ValidationContext(test, null, null);

    // No exception here! (why not?)
    Validator.ValidateObject(test, context);

    test.MyProperty = null;

    // Exception here, as expected
    Validator.ValidateObject(test, context);
  }
}

For some reason, I do not get a validation exception when the string length is too long. I do get a validation exception (as expected) when I set the property to null and re-validate. Any ideas why my string length annotation is not being enforced?

Solution

  • It's a bit non-intuitive, but changing

    Validator.ValidateObject(test, context);

    to

    Validator.ValidateObject(test, context, true);

    solves the problem. The third argument is bool validateAllProperties. I'm not sure why the [Required] attribute was previously being enforced while the [StringLength] wasn't, but at least it all works now.