VB.net更改进程窗口不透明度

Question

我想将进程的不透明度更改为80％（0.8），

类似的东西：

Declare Function changePopacity Lib "user32.dll" (ByVal p As process,byval howmach as intager)

for each p as process in process.getprocesses()

if p.name = "firefox" then
changePopacity(p,8)
end if

next

功能是什么？