Record Key Press From Outside The Application (VB.net) [duplicate]

问题

I am making a program which uses the function of a keylogger to determine trends, the problem is I can't make the keylogger, I have most of it complete but I can't get key presses when the form is out of focus... I have seen people mentioning keyboard and message hooks, but I can't find any examples or understand any documents on it.

Private Sub Form1_KeyPress(sender As Object, e As KeyPressEventArgs) Handles MyBase.KeyPress
    Using sw As StreamWriter = File.AppendText(Path) ' Open keylog file for editing
        If Asc(e.KeyChar) = 13 Then ' If key pressed is Enter...
            sw.Write("|Enter|") ' Append "|Enter|"
        ElseIf Asc(e.KeyChar) = 8 Then ' If key pressed is Backspace...
            sw.Write("|Backspace|") ' Append "|Backspace|"
        Else
            sw.Write(e.KeyChar) ' Otherwise append character
        End If
    End Using
End Sub

As you can see I have the recording of the keys and everything, I just need to be able to get key presses when the application is minimized or out of focus.

Thanks in advance.

回答1:

This works perfectly...

Imports System.IO

Public Class Form1

    Dim Path As String = "C:\Users\user\Desktop\keys.log" ' Keylog file location
    Private WithEvents kbHook As New KeyboardHook

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        If My.Computer.FileSystem.FileExists(Path) = False Then ' If keylog file doesn't exist...
            File.CreateText(Path) ' Create keylog file
        End If
    End Sub

    Private Sub kbHook_KeyDown(ByVal Key As Keys) Handles kbHook.KeyDown
        Using sw As StreamWriter = File.AppendText(Path) ' Open keylog file for editing
            sw.Write(Key.ToString) ' Append character
        End Using
    End Sub
End Class

I put the KeyboardHook class in a separate file to keep it out the way for when I need to fix something else in the Form1 class. I would advise this unless you don't need to add anything else to your program.

Imports System.Runtime.InteropServices

Public Class KeyboardHook

    <DllImport("User32.dll", CharSet:=CharSet.Auto, CallingConvention:=CallingConvention.StdCall)>
    Private Overloads Shared Function SetWindowsHookEx(ByVal idHook As Integer, ByVal HookProc As KBDLLHookProc, ByVal hInstance As IntPtr, ByVal wParam As Integer) As Integer
    End Function
    <DllImport("User32.dll", CharSet:=CharSet.Auto, CallingConvention:=CallingConvention.StdCall)>
    Private Overloads Shared Function CallNextHookEx(ByVal idHook As Integer, ByVal nCode As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As Integer
    End Function
    <DllImport("User32.dll", CharSet:=CharSet.Auto, CallingConvention:=CallingConvention.StdCall)>
    Private Overloads Shared Function UnhookWindowsHookEx(ByVal idHook As Integer) As Boolean
    End Function

    <StructLayout(LayoutKind.Sequential)>
    Private Structure KBDLLHOOKSTRUCT
        Public vkCode As UInt32
        Public scanCode As UInt32
        Public flags As KBDLLHOOKSTRUCTFlags
        Public time As UInt32
        Public dwExtraInfo As UIntPtr
    End Structure

    <Flags()>
    Private Enum KBDLLHOOKSTRUCTFlags As UInt32
        LLKHF_EXTENDED = &H1
        LLKHF_INJECTED = &H10
        LLKHF_ALTDOWN = &H20
        LLKHF_UP = &H80
    End Enum

    Public Shared Event KeyDown(ByVal Key As Keys)
    Public Shared Event KeyUp(ByVal Key As Keys)

    Private Const WH_KEYBOARD_LL As Integer = 13
    Private Const HC_ACTION As Integer = 0
    Private Const WM_KEYDOWN = &H100
    Private Const WM_KEYUP = &H101
    Private Const WM_SYSKEYDOWN = &H104
    Private Const WM_SYSKEYUP = &H105

    Private Delegate Function KBDLLHookProc(ByVal nCode As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As Integer

    Private KBDLLHookProcDelegate As KBDLLHookProc = New KBDLLHookProc(AddressOf KeyboardProc)
    Private HHookID As IntPtr = IntPtr.Zero

    Private Function KeyboardProc(ByVal nCode As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As Integer
        If (nCode = HC_ACTION) Then
            Dim struct As KBDLLHOOKSTRUCT
            Select Case wParam
                Case WM_KEYDOWN, WM_SYSKEYDOWN
                    RaiseEvent KeyDown(CType(CType(Marshal.PtrToStructure(lParam, struct.GetType()), KBDLLHOOKSTRUCT).vkCode, Keys))
                Case WM_KEYUP, WM_SYSKEYUP
                    RaiseEvent KeyUp(CType(CType(Marshal.PtrToStructure(lParam, struct.GetType()), KBDLLHOOKSTRUCT).vkCode, Keys))
            End Select
        End If
        Return CallNextHookEx(IntPtr.Zero, nCode, wParam, lParam)
    End Function

    Public Sub New()
        HHookID = SetWindowsHookEx(WH_KEYBOARD_LL, KBDLLHookProcDelegate, Marshal.GetHINSTANCE(System.Reflection.Assembly.GetExecutingAssembly.GetModules()(0)).ToInt32, 0)
        If HHookID = IntPtr.Zero Then
            Throw New Exception("Could not set keyboard hook")
        End If
    End Sub

    Protected Overrides Sub Finalize()
        If Not HHookID = IntPtr.Zero Then
            UnhookWindowsHookEx(HHookID)
        End If
        MyBase.Finalize()
    End Sub

End Class

来源：https://stackoverflow.com/questions/40208291/record-key-press-from-outside-the-application-vb-net

标签

vb.net

keyboard-hook

keylogger