public Filter CreateFilter()
        {
            var expression = new FilterExpression();
            var dataType   = PropertyTypes.Parse(_dataType);
            var value      = Convert.ChangeType(_value, dataType);

            if (dataType == typeof(int))
            {
                return(expression.NotEqual(_field, (int)value));
            }

            if (dataType == typeof(string))
            {
                return(expression.NotEqual(_field, (string)value));
            }

            if (dataType == typeof(DateTime))
            {
                return(expression.NotEqual(_field, (DateTime)value));
            }

            if (dataType == typeof(decimal))
            {
                return(expression.NotEqual(_field, (decimal)value));
            }

            throw new NotSupportedException("Unsupported data type: " + _dataType);
        }