我其实只是想出了答案。谢谢大家既为你的答案，但事实证明，我必须做的是这样的：

I've actually just figured out the answer. Thank you both for your answers, but it turns out that all i had to do was this:

p.StandardInput.Close()

这将导致我产生了要完成从标准输入和输出读什么我需要的程序。

which causes the program I've spawned to finish reading from stdin and output what i need.