Question

vb findwindow用法，，，入门。

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

Private Sub Command1_Click()
k = FindWindow(0, "登陆")
If k = 0 Then
MsgBox " 未找到窗口", 48, "提示"
Else
MsgBox "找到窗口，请确认", 48, "提示"
End If
End Sub

为什么总是返回的是0，那个登陆程序是我自己做的。里面就加了一句me.caption="登陆"
为什么呢？麻烦解答。

Answer 1

k = FindWindow(vbNullString, "登陆")

=======================================
示例：
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Declare Function SetWindowText Lib "user32" Alias "SetWindowTextA" (ByVal hwnd As Long, ByVal lpString As String) As Long

Private Sub Command1_Click()
Dim hw&
hw& = FindWindow(vbNullString, "计算器")
If hw Then SetWindowText hw, "这样不好吧！"
End Sub

Answer 2

k = FindWindow(vbNullString, "登陆")
不能用0，要使用vbNullString

Answer 3

k = FindWindow(vbnollstring, "登陆")