ValidationRule error only half working...

[Elrond]

I have created a validation rule to validate that the value in a textbox is within a certain range.

class ValueValidationRule : ValidationRule
{
	private int _min = 0;
	private int _max = 0;
	public ValueValidationRule(int min, int max)
	{
		_min = min;
		_max = max;
	}

	public override ValidationResult Validate(object source, CultureInfo info)
	{
		int value = 0;
		try
		{
			value = Convert.ToInt32(source);
			if (value >= _min && value <= _max)
			{
				return ValidationResult.ValidResult;
			}
			else
			{
				return new ValidationResult(false, "out of range");
			}
		}
		catch (Exception)
		{
			return new ValidationResult(false, "wrong format!");
		}
	}
}

When the value cannot be converted, the error "wrong format!" shows well. But when the value is out of range, even though I have put a break point that proves that the other invalid result ("out of range") is actually reached, it does not show as an error.

Here is the binding:

			
Binding testbind = new Binding();
testbind .Path = new PropertyPath("Value");
testbind .UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged;
testbind .ValidationRules.Add(new ValueValidationRule(1, 10));
testbind .NotifyOnValidationError = true;
testbind .TargetNullValue = 0;
codeBinding.SetBinding(TextBox.TextProperty, testbind);