VB 判断窗体失去焦点

思路,用windows API函数 GetForegroundWindow 得到前台窗口的句柄,然后跟窗口的句柄比较... 如果相同就是得到焦点,否则失去焦点,例子中我用的timer检测,,,,,,代码如下 Option ExplicitPrivate Declare Function GetForegroundWindow Lib "user32" () As Long
Private Sub Form_Load()
Timer1.Interval = 10
End SubPrivate Sub Timer1_Timer()
Dim thwnd As Long
thwnd = GetForegroundWindow
If thwnd <> Me.hWnd Then
Me.Caption = "失去焦点"
Else
Me.Caption = "得到焦点"
End If
End Sub

'第一种:这下只能在多窗口程序中有效：Private Sub Form_Deactivate()
MsgBox "失去焦点了"
End Sub '第二种:要用API：'添加一个定时器，interval设为1000Private Declare Function GetActiveWindow Lib "user32" () As Long
Dim H As Long
Private Sub Timer1_Timer()
H = GetActiveWindow
If H <> Me.hWnd Then
MsgBox "失去焦点"
End If
End Sub

简单点的方法是：
在窗体上放一个Timer，将Interval设为100。然后输入以下代码：
Private Declare Function GetForegroundWindow Lib "user32" () As Long

Private Sub Timer1_Timer()
If GetForegroundWindow() <> hWnd Then StartSecurity
End Sub