Re: VB, sending messages to another app using SendMessage / PostMessage.

First, this is not a dotnet group, look for newsgroups that has "dotnet" or
"vsnet" in the name...

Second, AFAIK, only WM_GETTEXT and WM_SETTEXT will work across process
boundaries(Between 2 EXE's). Windows will transport the text back and forth
between the 2 processes. This is done for backward compatibility. Other
messages could crash the target application(or your application, or the IDE)
because the data are not shared. In most cases, a pointer in one process
that is pointing to a "Hello" string is pointing to garbage characters in
the other process, but sometimes these garbage characters are zeros, so the
string is considered a null string. In Windows, a pointer in one process is
not valid in another process.

It's important when you use WM_GETTEXT to allocate enough buffer to for the
text by adding a line before the call like the following:

buffer = Space(2000)

Save your work before each compile or run, it's most likely the IDE will
crash until you get it right.

<DarthContinent@xxxxxxxxx> wrote in message
news:1125982172.882901.168660@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> Hello, could someone more fluent than I in VB please examine the
> following and help me understand where the problem may lie?
>
> Basically I begin by grabbing the handle to an "edit" control within
> the main program (a game, Jedi Academy), and try to input text into
> that control using SendMessage.
>
> However, no matter what I've tried so far I can't seem to get any
> reaction from the game, I get no feedback whatsoever indicating that
> the messages I'm expecting have been successfully received. I get a
> nonzero value in response to FindWindow / FindWindowEx, which I
> understand indicates that the handle was acquired successfully, so I'm
> pretty sure I'm grabbing the right handle, it's just not going from
> there.
>
> Could it be an issue with focus? Does the app I'm grabbing a handle to
> need to have the focus before it will accept and process messages in
> this way?
>
> Or are my function definitions somehow incorrect / incomplete?
>
> Any suggestions would be appreciated, I've scoured the newsgroups and
> I'm afraid I haven't been able to gather much to help me out of my own
> hole.
>
> ---
>
> <BEGIN CODE>
>
>
> Imports System.Runtime.InteropServices
> Public Class Form1
> Inherits System.Windows.Forms.Form
>
> #Region " Windows Form Designer generated code "
>
> Public Sub New()
> MyBase.New()
>
> 'This call is required by the Windows Form Designer.
> InitializeComponent()
>
> 'Add any initialization after the InitializeComponent() call
>
> End Sub
>
> 'Form overrides dispose to clean up the component list.
> Protected Overloads Overrides Sub Dispose(ByVal disposing As
> Boolean)
> If disposing Then
> If Not (components Is Nothing) Then
> components.Dispose()
> End If
> End If
> MyBase.Dispose(disposing)
> End Sub
>
> 'Required by the Windows Form Designer
> Private components As System.ComponentModel.IContainer
>
> 'NOTE: The following procedure is required by the Windows Form
> Designer
> 'It can be modified using the Windows Form Designer.
> 'Do not modify it using the code editor.
> Friend WithEvents Button1 As System.Windows.Forms.Button
> Friend WithEvents TextBox1 As System.Windows.Forms.TextBox
> Friend WithEvents Label2 As System.Windows.Forms.Label
> Friend WithEvents Label3 As System.Windows.Forms.Label
> <System.Diagnostics.DebuggerStepThrough()> Private Sub
> InitializeComponent()
> Me.Button1 = New System.Windows.Forms.Button
> Me.TextBox1 = New System.Windows.Forms.TextBox
> Me.Label2 = New System.Windows.Forms.Label
> Me.Label3 = New System.Windows.Forms.Label
> Me.SuspendLayout()
> '
> 'Button1
> '
> Me.Button1.Location = New System.Drawing.Point(16, 48)
> Me.Button1.Name = "Button1"
> Me.Button1.Size = New System.Drawing.Size(264, 32)
> Me.Button1.TabIndex = 0
> Me.Button1.Text = "send string in textbox to other app"
> '
> 'TextBox1
> '
> Me.TextBox1.Location = New System.Drawing.Point(16, 16)
> Me.TextBox1.Name = "TextBox1"
> Me.TextBox1.Size = New System.Drawing.Size(264, 20)
> Me.TextBox1.TabIndex = 1
> Me.TextBox1.Text = "some sample text"
> '
> 'Label2
> '
> Me.Label2.Location = New System.Drawing.Point(16, 96)
> Me.Label2.Name = "Label2"
> Me.Label2.Size = New System.Drawing.Size(256, 24)
> Me.Label2.TabIndex = 3
> Me.Label2.Text = "Label2"
> '
> 'Label3
> '
> Me.Label3.Location = New System.Drawing.Point(16, 128)
> Me.Label3.Name = "Label3"
> Me.Label3.Size = New System.Drawing.Size(256, 24)
> Me.Label3.TabIndex = 4
> Me.Label3.Text = "Label3"
> '
> 'Form1
> '
> Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
> Me.ClientSize = New System.Drawing.Size(292, 165)
> Me.Controls.Add(Me.Label3)
> Me.Controls.Add(Me.Label2)
> Me.Controls.Add(Me.TextBox1)
> Me.Controls.Add(Me.Button1)
> Me.Name = "Form1"
> Me.Text = "WM_send"
> Me.ResumeLayout(False)
>
> End Sub
>
> #End Region
>
>
> Dim wndh As Integer 'handle to some app window
> Dim wndh2 As Integer
>
>
> 'Win32 api declarations
> Private Structure COPYDATASTRUCT
> Public dwData As Integer
> Public cbData As Integer
> Public lpData As Integer
> End Structure
>
> Const WM_COPYDATA As Int32 = &H4A
> Const EM_GETSEL As Int32 = &HB0
> Const EM_SETSEL As Int32 = &HB1
> Const EM_REPLACESEL As Int32 = &HC2
> Const WM_CHAR As Int32 = &H102
> Const WM_SETTEXT As Int32 = &HC
> Const WM_GETTEXT As Int32 = &HD
> Const WM_GETTEXTLENGTH As Int32 = &HE
> Const WM_CLOSE As Int32 = &H10
>
>
> Declare Function GetFocus Lib "user32" () As Long
> Declare Function SetFocus Lib "user32" (ByVal hwnd As Long) As Long
>
> Declare Function GetDlgCtrlID Lib "user32" (ByVal hwnd As Int32) As
> Int32
>
> Declare Function FindWindow Lib "user32.dll" Alias "FindWindowA"
> (ByVal lpClassName As String, ByVal lpWindowName As String) As Int32
>
> Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA"
> (ByVal hWnd1 As Int32, ByVal hWnd2 As Int32, ByVal lpsz1 As String,
> ByVal lpsz2 As String) As Int32
>
> Declare Function PostMessageByString Lib "user32" Alias
> "PostMessageA" (ByVal hwnd As Int32, ByVal wMsg As Int32, ByVal wParam
> As Int32, ByVal lParam As String) As Int32
>
> Declare Function SendMessage Lib "user32" Alias "SendMessageA"
> (ByVal hwnd As Int32, ByVal wMsg As Int32, ByVal wParam As Int32, ByVal
> ByVallParam As Int32) As Int32
>
> Declare Function SendMessageLong& Lib "user32" Alias "SendMessageA"
> (ByVal hwnd As Int32, ByVal wMsg As Int32, ByVal wParam As Int32, ByVal
> lParam As Int32)
>
> Declare Function SendMessageBystring Lib "user32" Alias
> "SendMessageA" (ByVal hwnd As Int32, ByVal wMsg As Int32, ByVal wParam
> As Int32, ByVal lParam As String) As Int32
>
> Declare Function SetWindowText Lib "User32.dll" Alias
> "SetWindowTextA" (ByVal hWnd As Int32, ByVal lpString As String) As
> Int32
>
>
>
> 'Button to send message
> Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
> System.EventArgs) Handles Button1.Click
>
> 'Get handle to app (wndh) and control within app (wndh2)
>
> wndh = FindWindow("JAMP WinConsole", "Jedi Knight Academy MP
> Console")
> wndh2 = FindWindowEx(wndh, 0, "Edit", vbNullString)
> wndh2 = FindWindowEx(wndh, wndh2, "Edit", vbNullString)
>
> SetFocus(wndh2)
>
> SendMessage(wndh2, EM_SETSEL, -1, -1)
> SendMessageBystring(wndh2, EM_REPLACESEL, 0, "say test")
> SendMessageLong(wndh2, WM_CHAR, 13, 0&)
>
> End Sub
>
>
> <END CODE>
>


.

Loading