StreamReader 不见了?

StreamReader is missing?

我可以做些什么来修改它吗?

A using namespace directive can only be applied to namespaces; 'System.IO.StreamReader' is a type not a namespace

查看 "add a reference" 并且 StreamReader 在可供选择的选项列表中不可用。

using System.IO;
using System.IO.StreamReader;
using System.IO;
//THATS TOO MUCH : using System.IO.StreamReader;