SetWindowLong Does'nt work with old window

N

night_prince

Member
Joined
Dec 17, 2006
Messages
24
Programming Experience
Beginner
Hi
i think some of you will think i'm API Crazy :)


i'm trying to get another application messages like Spy++ program

i used the usual way :

hwnd=FindWindow( .....)
PrevHwnd=SetWinowLong(hwnd , GW_WNDPROC, (Addressof WndPoc))

Function wnd(hwnd as intptr,msg as integer,wparam as integer,wparam as integer)



End Function
...etc

The proplem is that this code doesnt works with ( as i think ) unmanaged Code , because i made an application with vb6 which has one form
and tried this code with that Form but it didnt work .

and when i use GetLastError i got an "invalid window Handle" Message

but when i tried it with same application or another application made by vb.net it worked.


Can any one help me .:(
 
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Here Are My Code :
VB.NET: 
[SIZE=2][COLOR=#0000ff][SIZE=2][COLOR=#0000ff]Imports[/COLOR][/SIZE][SIZE=2][COLOR=#000000] System.Runtime.InteropServices[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Public[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Class[/COLOR][/SIZE][SIZE=2][COLOR=#000000] Main[/COLOR][/SIZE]
[SIZE=2][COLOR=#008000]'---------------------------------------------------------------------------------[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Private[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Declare[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Function[/COLOR][/SIZE][SIZE=2] SetWindowLong [/SIZE][SIZE=2][COLOR=#0000ff]Lib[/COLOR][/SIZE][SIZE=2][COLOR=#800000]"user32.dll"[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Alias[/COLOR][/SIZE][SIZE=2] _[/SIZE]
[SIZE=2][COLOR=#800000]"SetWindowLongA"[/COLOR][/SIZE][SIZE=2] ([/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] hwnd [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2], [/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] nIndex [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2], [/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] dwNewinteger [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2]) [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE]
[SIZE=2][COLOR=#008000]'---------------------------------------------------------------------------------[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Private[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Declare[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Function[/COLOR][/SIZE][SIZE=2] FindWindow [/SIZE][SIZE=2][COLOR=#0000ff]Lib[/COLOR][/SIZE][SIZE=2][COLOR=#800000]"user32.dll"[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Alias[/COLOR][/SIZE][SIZE=2] _[/SIZE]
[SIZE=2][COLOR=#800000]"FindWindowA"[/COLOR][/SIZE][SIZE=2] ([/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] lpClassName [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]String[/COLOR][/SIZE][SIZE=2], [/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] lpWindowName [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]String[/COLOR][/SIZE][SIZE=2]) [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE]
[SIZE=2][COLOR=#008000]'---------------------------------------------------------------------------------[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Private[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Declare[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Function[/COLOR][/SIZE][SIZE=2] CallWindowProc [/SIZE][SIZE=2][COLOR=#0000ff]Lib[/COLOR][/SIZE][SIZE=2][COLOR=#800000]"user32.dll"[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Alias[/COLOR][/SIZE][SIZE=2] _[/SIZE]
[SIZE=2][COLOR=#800000]"CallWindowProcA"[/COLOR][/SIZE][SIZE=2] ([/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] lpPrevWndFunc [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2], [/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] hwnd [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2], [/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] msg [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2], [/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] wParam [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2], [/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] lParam [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2]) [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE]
[SIZE=2][COLOR=#008000]'---------------------------------------------------------------------------------[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Private[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Const[/COLOR][/SIZE][SIZE=2] GWL_WNDPROC [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2] = -4[/SIZE]
[SIZE=2][COLOR=#008000]'---------------------------------------------------------------------------------[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Public[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Delegate[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Function[/COLOR][/SIZE][SIZE=2] Proc _[/SIZE]
[SIZE=2]([/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] hwnd [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] IntPtr, [/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] msg [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2], _[/SIZE]
[SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] wparam [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2], [/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] lparam [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2]) [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE]
[SIZE=2][COLOR=#008000]'---------------------------------------------------------------------------------[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Private[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Sub[/COLOR][/SIZE][SIZE=2] Form1_FormClosing([/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] sender [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Object[/COLOR][/SIZE][SIZE=2], _[/SIZE]
[SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] e [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] System.Windows.Forms.FormClosingEventArgs) [/SIZE][SIZE=2][COLOR=#0000ff]Handles[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].FormClosing[/SIZE]
[SIZE=2]SetWindowLong(hwnd, GWL_WNDPROC, PrevProc)[/SIZE]
[SIZE=2][COLOR=#0000ff]End[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Sub[/COLOR][/SIZE]
[SIZE=2][COLOR=#008000]'---------------------------------------------------------------------------------[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] hwnd [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] IntPtr[/SIZE]
[SIZE=2][COLOR=#0000ff]Private[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Sub[/COLOR][/SIZE][SIZE=2] Form1_Load([/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] sender [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] System.Object, [/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] e [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] System.EventArgs) _[/SIZE]
[SIZE=2][COLOR=#0000ff]Handles[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]MyBase[/COLOR][/SIZE][SIZE=2].Load[/SIZE]
[SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] ProcDel [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]New[/COLOR][/SIZE][SIZE=2] Proc([/SIZE][SIZE=2][COLOR=#0000ff]AddressOf[/COLOR][/SIZE][SIZE=2] WindProc)[/SIZE]
[SIZE=2][COLOR=#008000]' Now try to change the next line to[/COLOR][/SIZE]
[SIZE=2][COLOR=#008000]'hwnd = me.handle[/COLOR][/SIZE]
[SIZE=2][COLOR=#008000]'or make another application with .NET with any Form it will works[/COLOR][/SIZE]
[SIZE=2][COLOR=#008000]'hwnd = FindWindow(vbNullString, "Form1")[/COLOR][/SIZE]
[SIZE=2]hwnd = FindWindow(vbNullString, [/SIZE][SIZE=2][COLOR=#800000]"Calculator"[/COLOR][/SIZE][SIZE=2])[/SIZE]
[SIZE=2]PrevProc = SetWindowLong(hwnd, GWL_WNDPROC, _[/SIZE]
[SIZE=2]Marshal.GetFunctionPointerForDelegate(ProcDel))[/SIZE]
[SIZE=2][COLOR=#0000ff]End[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Sub[/COLOR][/SIZE]
[SIZE=2][COLOR=#008000]'---------------------------------------------------------------------------------[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] PrevProc [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE]
[SIZE=2][COLOR=#008000]'---------------------------------------------------------------------------------[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Public[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Function[/COLOR][/SIZE][SIZE=2] WindProc([/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] hwnd [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] IntPtr, _[/SIZE]
[SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] msg [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2], [/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] wparam [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2], [/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] lparam [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2]) [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE]
[SIZE=2]Debug.Print(msg.ToString)[/SIZE]
[SIZE=2][COLOR=#0000ff]Return[/COLOR][/SIZE][SIZE=2] CallWindowProc(PrevProc, hwnd, msg, wparam, lparam)[/SIZE]
[SIZE=2][COLOR=#0000ff]End[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Function[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]End[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Class[/COLOR][/SIZE]
[/COLOR][/SIZE]


;)
 
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VB.NET: 
hwnd = FindWindow(vbNullString, "Calculator")

I'm interested to know how that code even compiles. I didn't think that vbNullString was valid in vb.net?
 
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SetWindowLong was the classic VB way of subclassing, it only works with windows within your own process. With VB.Net you don't need this, .Net provides inheritance that easily allow you to modify standard controls and get access to internals which classic VB didn't. .Net also opens the message pump for the developer through the forms/controls overridable WndProc method.

I know no method of VB.Net to get other process windows messages.
 
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