rcherne1
asked on
How do I make a hook to copy a result from windows calculator?
Let me give you an example of what I’m looking for. Lets say I have a button on a vb form that activates the windows calculator. I what to do the math, but When I close the “Calculator App" I want to copy the result to a text box in my vb app.
oops, I guess you can't use GetWindowText across apps, but you can use WM_GetText, here is code for the hack version. It's just a form with a button. The button will launch calculator and get the result when you close the calculator.
Option Explicit
Private Const WM_GETTEXT = &HD
Private Const GW_CHILD = 5
Private Const GW_HWNDNEXT = 2
Private Declare Function GetDesktopWindow Lib "user32" () As Long
Private Declare Function GetWindow Lib "user32" (ByVal hwnd As Long, ByVal wCmd As Long) As Long
Private Declare Function GetWindowText Lib "user32" Alias "GetWindowTextA" (ByVal hwnd As Long, ByVal lpString As String, ByVal cch As Long) As Long
Private Declare Function GetClassName Lib "user32" Alias "GetClassNameA" (ByVal hwnd As Long, ByVal lpClassName As String, ByVal nMaxCount As Long) As Long
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)
Private Sub Command1_Click()
Dim CalcWindow As Long
Dim CalcText As String
Dim erc As Long
Shell "C:\windows\System32\calc. exe"
CalcWindow = FindCalculatorWindow
If CalcWindow <> 0 Then
Do
erc = GetCalculatorText(CalcWind ow, CalcText)
Sleep (50)
Loop Until erc <> 0
End If
MsgBox CalcText
End Sub
Function FindCalculatorWindow() As Long
Dim desktop As Long
Dim calculator As Long
Dim textbox As Long
Dim buffer As String * 200
Dim bufflen As Long
Dim bytearray(200) As Byte
desktop = GetDesktopWindow()
calculator = GetWindow(desktop, GW_CHILD)
Do While calculator <> 0
bufflen = GetWindowText(calculator, buffer, 200)
If Left(buffer, 10) = "Calculator" Then
Exit Do
End If
calculator = GetWindow(calculator, GW_HWNDNEXT)
Loop
If calculator = 0 Then
MsgBox "Could not find calculator!"
Exit Function
End If
textbox = GetWindow(calculator, GW_CHILD)
Do While textbox <> 0
bufflen = GetClassName(textbox, buffer, 200)
If Left(buffer, 4) = "Edit" Then
Exit Do
End If
textbox = GetWindow(textbox, GW_HWNDNEXT)
Loop
If textbox = 0 Then
MsgBox "Could not find text box in calculator"
Exit Function
End If
FindCalculatorWindow = textbox
End Function
Function GetCalculatorText(hwnd As Long, ByRef result As String) As Long
Dim bufflen As Long
Dim bytearray(200) As Byte
Dim i As Integer
Dim Answer As String
bufflen = SendMessage(hwnd, WM_GETTEXT, 200, bytearray(0))
If bufflen > 0 Then
For i = 0 To bufflen - 1
Answer = Answer & Chr(bytearray(i))
Next
result = Answer
GetCalculatorText = 0
Else
GetCalculatorText = -1
'don't touch result
End If
End Function
Option Explicit
Private Const WM_GETTEXT = &HD
Private Const GW_CHILD = 5
Private Const GW_HWNDNEXT = 2
Private Declare Function GetDesktopWindow Lib "user32" () As Long
Private Declare Function GetWindow Lib "user32" (ByVal hwnd As Long, ByVal wCmd As Long) As Long
Private Declare Function GetWindowText Lib "user32" Alias "GetWindowTextA" (ByVal hwnd As Long, ByVal lpString As String, ByVal cch As Long) As Long
Private Declare Function GetClassName Lib "user32" Alias "GetClassNameA" (ByVal hwnd As Long, ByVal lpClassName As String, ByVal nMaxCount As Long) As Long
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)
Private Sub Command1_Click()
Dim CalcWindow As Long
Dim CalcText As String
Dim erc As Long
Shell "C:\windows\System32\calc.
CalcWindow = FindCalculatorWindow
If CalcWindow <> 0 Then
Do
erc = GetCalculatorText(CalcWind
Sleep (50)
Loop Until erc <> 0
End If
MsgBox CalcText
End Sub
Function FindCalculatorWindow() As Long
Dim desktop As Long
Dim calculator As Long
Dim textbox As Long
Dim buffer As String * 200
Dim bufflen As Long
Dim bytearray(200) As Byte
desktop = GetDesktopWindow()
calculator = GetWindow(desktop, GW_CHILD)
Do While calculator <> 0
bufflen = GetWindowText(calculator, buffer, 200)
If Left(buffer, 10) = "Calculator" Then
Exit Do
End If
calculator = GetWindow(calculator, GW_HWNDNEXT)
Loop
If calculator = 0 Then
MsgBox "Could not find calculator!"
Exit Function
End If
textbox = GetWindow(calculator, GW_CHILD)
Do While textbox <> 0
bufflen = GetClassName(textbox, buffer, 200)
If Left(buffer, 4) = "Edit" Then
Exit Do
End If
textbox = GetWindow(textbox, GW_HWNDNEXT)
Loop
If textbox = 0 Then
MsgBox "Could not find text box in calculator"
Exit Function
End If
FindCalculatorWindow = textbox
End Function
Function GetCalculatorText(hwnd As Long, ByRef result As String) As Long
Dim bufflen As Long
Dim bytearray(200) As Byte
Dim i As Integer
Dim Answer As String
bufflen = SendMessage(hwnd, WM_GETTEXT, 200, bytearray(0))
If bufflen > 0 Then
For i = 0 To bufflen - 1
Answer = Answer & Chr(bytearray(i))
Next
result = Answer
GetCalculatorText = 0
Else
GetCalculatorText = -1
'don't touch result
End If
End Function
In theory, you should be able to use FindWindowEx to find the textbox instead of my loops, but for some reason FindWindowEx never works for me.
To get the edit window handle of calculator using FindWindowEx, use:
'Get the handle of the Edit window of Calc
lhWndEdit = FindWindowEx(lhWnd, 0, "Edit", vbNullString)
where
lhWnd is the main window handle of calculator.
'Get the handle of the Edit window of Calc
lhWndEdit = FindWindowEx(lhWnd, 0, "Edit", vbNullString)
where
lhWnd is the main window handle of calculator.
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VB6 or .net?
In VB 6, a hack would be to shell the calculator, and keep reading the text box value until the calculator goes away, the last value you get should be the value you want.
In VB.net, you could hook into the windows callbacks that announce when an application is closing, and grab your data then