System.Object.Equals C# (CSharp) Method

    public virtual bool Equals(Object obj)
    {
        return InternalEquals(this, obj);
    }

 //"x in y" should return true whenever "for (var z in y) if (z === x) return true" returns true
 public static bool JScriptIn(Object v1, Object v2){
   bool result = false;
   if (v2 is ScriptObject)
     return !(((ScriptObject)v2).GetMemberValue(Convert.ToString(v1)) is Missing);
   else if (v2 is Array){
     Array arr = (Array)v2;
     double d = Convert.ToNumber(v1);
     int i = (int)d;
     return d == i && arr.GetLowerBound(0) <= i && i <= arr.GetUpperBound(0);
   }else if (v2 is IEnumerable){
     if (v1 == null) return false;
     //Do not enumerate when a direct lookup is available
     if (v2 is IDictionary)
       return ((IDictionary)v2).Contains(v1);
     if (v2 is IExpando){
       MemberInfo[] members = ((IReflect)v2).GetMember(Convert.ToString(v1), BindingFlags.Instance|BindingFlags.DeclaredOnly|BindingFlags.Public);
       return members.Length > 0;
     }
     IEnumerator enu = ((IEnumerable)v2).GetEnumerator();
     while (!result && enu.MoveNext())
       if (v1.Equals(enu.Current)) return true;
   }else if (v2 is IEnumerator){
     if (v1 == null) return false;          
     IEnumerator enu = (IEnumerator)v2;
     while (!result && enu.MoveNext())
       if (v1.Equals(enu.Current)) return true;
   }
   throw new JScriptException(JSError.ObjectExpected);
 }