Getting property accValue of IAccessible throws an error. #14

using System.Windows.Automation;

public object GetValue(AutomationElement element){
            object patternObj;
            if (element.TryGetCurrentPattern(LegacyIAccessiblePattern.Pattern, out patternObj))
            {
                var legacyIAccessiblePattern = (LegacyIAccessiblePattern)patternObj;
                var iAccessible = legacyIAccessiblePattern.GetIAccessible();

                if (iAccessible != null)
                {
                    result = iAccessible.accValue; // ERROR HERE
                }
            }
            return Accessible.accValue;
}