请问windows API函数怎么知道？怎么用呢？

Question

我按照vb书上做透明窗体效果，用到了api函数，可是我的这个显示找不到那个dll文件，请问这个是怎么回事？
是不是操作系统不一样了？

Answer 1

Public Declare Function SetLayeredWindowAttributes Lib _
"user32" (ByVal hnd As Long, ByVal clval As Long, _
ByVal alph As Byte, ByVal flago As Long) As Long

Public Declare Function GetWindowLong Lib "user32" Alias _
"GetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long) As Long

Public Declare Function SetWindowLong Lib "user32" Alias _
"SetWindowLongA" (ByVal hnd As Long, ByVal nIndex As Long, _
ByVal dwNewLong As Long) As Long

Public Const LWA_ALPHA = &H2&
Public Const LWA_COLORKEY = &H1&
Public Const GWL_EXSTYLE = (-20)
Public Const WS_EX_LAYERED = &H80000
Public Const WS_EX_TRANSPARENT = &H20&
你肯定是打错字了。。。比如多打了".dll"
声明最好用“API Viewer” 或者上网找
找的方法把函数名打上搜就可以找到声明了。因为好多API“API Viewer”里面没有。。

Answer 2

你添加对那个API函数的引用没有，用外接程序下面的“API Viewer”