如何在委托中指定枚举

Question

我的表达是

Expression<Func<TSource,TResult>>

对于其他原始类型

我正在创建表达式

Expression<Func<TSource,int>>, Expression<Func<TSource,string>>

但是如果在枚举

的情况下如何指定TResult

实施例

getExpression<TSource, int>(expression)// for integer
getExpression<TSource, string>(expression) // for string
getExpression<TSource, Enum>(expression) // It reruns null

private Expression<Func<TSource, TResult>> getExpression<TSource, TResult>(Expression expression)
        {
            var x = expression as Expression<Func<TSource, TMember>>;

            return x;
        }