SendInput VB Basic Example

Question

I hope someone can assist, I trying to find an example of a SendInput code that simulate keyboard commands, I wish to find the notepad window and enter a test message.

Answer 1

The following code is not for VB.net but VB/VBA, its similar to the sendkeys method but probably a little more reliable as it sends the keys specifically to the target application. (the post where i got it shows the sendkeys method too)

Public Declare Function FindWindowX Lib "user32" Alias "FindWindowExA" (ByVal hWnd1 As Long, _
ByVal hWnd2 As Long, ByVal lpsz1 As Long, ByVal lpsz2 As Long) As Long

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

Private Declare Function PostMessage Lib "user32" Alias "PostMessageA" (ByVal hwnd As Long, _
ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long

Public Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Integer, ByVal lParam As Integer) As Long

Private Const WM_KEYDOWN = &H100
Private Const WM_KEYUP = &H101

Sub Three()
    hWind = FindWindow(vbNullString, "Untitled - Notepad")
    cWind = FindWindowX(hWind, 0, 0, 0)
    Debug.Print PostMessage(cWind, WM_KEYDOWN, vbKeyA, 0)
    Debug.Print PostMessage(cWind, WM_KEYDOWN, vbKeyB, 0)
    Debug.Print PostMessage(cWind, WM_KEYDOWN, vbKeyC, 0)
End Sub

Code taken from this forum post

If you paste this into a new module in Excel/VBA and have an new instance of notepad running, when the sub is executed "abc" should appear in notepad.

I don't see how using this, or the sendkeys method could "damage" the target window. So long as you time the messages properly (not sending tonnes of characters to the window all at the same time) it shouldn't cause any problems.

Answer 2

I had managed to find another SendInput script online, I have copied it below for anyone else who may be interested.

I have been using SendKeys to copy data from a spreadsheet and enter these on a system at work, this saves valuable time as there is a vast amount of information that needs to be entered.

The SendKeys function worked without any issues (although due to reliability issues I had to consider alternatives), will the SendInput cause any issues to the other window i.e. other than simulating keyboard buttons will it interfere with any other functions of the target window?

Private Declare Function SendInput Lib "user32.dll" _
 (ByVal nInputs As Long, ByRef pInputs As Any, _
 ByVal cbSize As Long) As Long
Private Declare Function VkKeyScan Lib "user32" Alias "VkKeyScanA" _
 (ByVal cChar As Byte) As Integer

Private Type KeyboardInput      '   typedef struct tagINPUT {
 dwType As Long                '     DWORD type;
 wVK As Integer                '     union {MOUSEINPUT mi;
 wScan As Integer              '               KEYBDINPUT ki;
 dwFlags As Long               '               HARDWAREINPUT hi;
 dwTime As Long                '              };
 dwExtraInfo As Long           '     }INPUT, *PINPUT;
 dwPadding As Currency         '   8 extra bytes, because mouses take more.
End Type

Private Const INPUT_MOUSE As Long = 0
Private Const INPUT_KEYBOARD As Long = 1
Private Const KEYEVENTF_KEYUP As Long = 2
Private Const VK_LSHIFT = &HA0

Public Sub SendKey(ByVal Data As String)
Dim ki() As KeyboardInput
Dim i As Long
Dim o As Long ' output buffer position
Dim c As String ' character

ReDim ki(1 To Len(Data) * 4) As KeyboardInput
o = 1

For i = 1 To Len(Data)
 c = Mid$(Data, i, 1)
 Select Case c
   Case "A" To "Z": ' upper case
     ki(o).dwType = INPUT_KEYBOARD 'shift down
     ki(o).wVK = VK_LSHIFT
     ki(o + 1) = ki(o) ' key down
     ki(o + 1).wVK = VkKeyScan(Asc(c))
     ki(o + 2) = ki(o + 1) ' key up
     ki(o + 2).dwFlags = KEYEVENTF_KEYUP
     ki(o + 3) = ki(o) ' shift up
     ki(o + 3).dwFlags = KEYEVENTF_KEYUP
     o = o + 4
   Case Else: ' lower case
     ki(o).dwType = INPUT_KEYBOARD
     ki(o).wVK = VkKeyScan(Asc(c))
     ki(o + 1) = ki(o)
     ki(o + 1).dwFlags = KEYEVENTF_KEYUP
     o = o + 2
 End Select
Next i

Debug.Print SendInput(o - 1, ki(1), LenB(ki(1))),
'Debug.Print Err.LastDllError
End Sub

Private Sub Command1_Click()
Text1.Text = ""
Text1.SetFocus
DoEvents
Call SendKey("This Is A Test")
End Sub