Question

VB中的FindWindow返回值一直为0

Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long

Private Sub Form_Load()
Dim hWnd As Long
Dim x As String

Do While x <> "a"
hWnd = FindWindow(0&, 0&)
x = InputBox(hWnd)
Loop

End Sub

可以看到hWnd一直是0，不知道是为什么

Answer 1

Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Sub Form_Load()
    Dim hWnd As Long
    Dim x As String
    
    Do While x <> 0
        hWnd = FindWindow(vbNullString, x)
        x = InputBox(hWnd)
    Loop
    
End Sub

FindWindow里需要传入值才能获取句柄

追问

传入0的话是匹配任意类和窗口标题，不是吗

追答

那就用FindWindow(vbNullString, vbNullString)，传入空值

或者
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As Any, ByVal lpWindowName As Any) As Long

hWnd = FindWindow(0&, 0&)

Answer 2

对啊。。你想得到什么句柄，findwindow那行写错了，hWnd = FindWindow(vbNullString, "窗口的名字")