Visual Basic

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Module Module1<br />
    Declare Function GetCurrentThreadId Lib "kernel32" Alias "GetCurrentThreadId" () As Integer<br />
    Declare Function SetWindowsHookEx Lib "user32" Alias "SetWindowsHookExA" (ByVal idHook As Integer, ByVal lpfn As HOOKPROC, ByVal hmod As Integer, ByVal dwThreadId As Integer) As Integer<br />
    Declare Function UnhookWindowsHookEx Lib "user32" (ByVal hHook As Integer) As Integer<br />
    Declare Function CallNextHookEx Lib "user32" Alias "callnexthookex" (ByVal hHook As Integer, ByVal ncode As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer<br />
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    Public Delegate Function HOOKPROC(ByVal nCode As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer<br />
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    Private Declare Function GetAsyncKeyState Lib "user32" (ByVal vKey As Integer) As Integer<br />
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    Public hnexthookproc As Integer = 0<br />
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    Public Const PM_KEY_PrintScreen = &H2c<br />
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    Public Structure KbStruct<br />
        Dim vkCode As Integer<br />
        Dim ScanCode As Integer<br />
        Dim Flags As Integer<br />
        Dim Time As Integer<br />
        Dim dwExtraInfo As Integer<br />
    End Structure<br />
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    Public Enum HookType<br />
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        WH_KEYBOARD = 2<br />
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    End Enum<br />
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    Public Sub UnHook() 'close Hook <br />
        If hnexthookproc <> 0 Then<br />
            UnhookWindowsHookEx(hnexthookproc)<br />
            hnexthookproc = 0<br />
        End If<br />
    End Sub<br />
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    Public Function SetHook() 'set Hook <br />
        If hnexthookproc <> 0 Then<br />
            Exit Function<br />
        End If<br />
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        hnexthookproc = SetWindowsHookEx(HookType.WH_KEYBOARD, AddressOf MyKeyboardProc, 0, GetCurrentThreadId())<br />
    End Function<br />
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    Public Function MyKeyboardProc(ByVal nCode As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer<br />
        MyKeyboardProc = 0<br />
        If nCode < 0 Then<br />
            MyKeyboardProc = CallNextHookEx(hnexthookproc, nCode, wParam, lParam)<br />
            Exit Function<br />
        End If<br />
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        If wParam = PM_KEY_PrintScreen Then<br />
            MyKeyboardProc = 1<br />
            MsgBox("HOOK！")<br />
        End If<br />
    End Function<br />
End Module<br />

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Public Class Form1<br />
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    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load<br />
        Call SetHook()<br />
    End Sub<br />
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    Private Sub Form1_FormClosed(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosedEventArgs) Handles Me.FormClosed<br />
        Call UnHook()<br />
    End Sub<br />
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End Class<br />