Ive been struggling with the Win32 api call SendMessage and WM_COPYDATA to send strings to e.g. notepad using VB.NET 2005. Anyone has any sample code to share on how to do this?
With regards,
A
Ive been struggling with the Win32 api call SendMessage and WM_COPYDATA to send strings to e.g. notepad using VB.NET 2005. Anyone has any sample code to share on how to do this?
With regards,
A
Post your code please...
This is the current code im working on, its really an atempt to port some VB6 code that is working. The development platform is Vista 64-bit.
The FindWindowWild(TitleBarSearchName) provides a hWnd to the correct window, this has been verified using Spy++...
Things i need to consider later on is to assure its unicode being sent so
Code:Private Declare Auto Function SendMessage Lib "user32" (ByVal hwnd As IntPtr, ByVal wMsg As IntPtr, _
ByVal wParam As IntPtr, <MarshalAs(UnmanagedType.AnsiBStr)> ByVal lParam As String) As IntPtr
<StructLayout(LayoutKind.Sequential)> _
Private Structure CopyData
Public dwData As IntPtr
Public cbData As Integer
Public lpData As IntPtr
End Structure
Public Sub SendToApplication(ByVal TitleBarSearchName As String, ByVal strMessage As String)
Dim data As CopyData
' set up the data...
data.lpData = Marshal.StringToHGlobalAuto(strMessage)
data.cbData = strMessage.Length * Marshal.SystemDefaultCharSize
' send the data
SendMessage(FindWindowWild(TitleBarSearchName), WM_COPYDATA, IntPtr.Zero, data)
' free the pointer...
Marshal.FreeHGlobal(data.lpData)
SendMessage(FindWindowWild(TitleBarSearchName), New IntPtr(WM_COPYDATA), IntPtr.Zero, strMessage)
End Sub
Oh and here is another version im trying in parallell with..
VB Code:
How about the VB 6 Code?
Ok same goes here... FindWindowWild(TitleBarSearchName, False) provides the hWnd. This code works like a charm in all environments, its VB6 code. Compiled in VB6 this works on Vista too and does the trick.
vb Code:
what is FindWindowWild?
This function searches for a Window caption and returns a hwnd.
http://forums.microsoft.com/MSDN/Sho...09916&SiteID=1
I think this link is going to help...
Nope, already tried this code but without success... :(
I was able to get some unprintable binary garbage into notepad using this code:
Code:Imports System.Runtime.InteropServices
Public Class Form1
Private Const WM_COPYDATA As Integer = &H4A
Private Const WM_SETTEXT = &HC
Private Const WM_USER As Integer = &H400
<StructLayout(LayoutKind.Sequential)> _
Private Structure COPYDATASTRUCT
Public dwData As Integer
Public cbData As Integer
Public lpData As String
End Structure
<DllImport("user32.dll", SetLastError:=True)> _
Private Shared Function FindWindow( _
ByVal lpClassName As String, _
ByVal lpWindowName As String) As IntPtr
End Function
<DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _
Private Shared Function SendMessage( _
ByVal hWnd As HandleRef, _
ByVal Msg As UInteger, _
ByVal wParam As IntPtr, _
ByRef lParam As String) As IntPtr
End Function
Private Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hWnd1 As Integer, ByVal hWnd2 As Integer, ByVal lpsz1 As String, ByVal lpsz2 As String) As Integer
Public Sub SendToApplication(ByVal TitleBarSearchName As String, ByVal strMessage As String)
Dim cds As COPYDATASTRUCT
Dim SnapHandle As IntPtr = FindWindow(TitleBarSearchName, vbNullString)
Me.Text = SnapHandle.ToInt32.ToString
If Not SnapHandle = 0 Then
Dim href As New HandleRef(Me, SnapHandle)
Dim SnapHandle2 As IntPtr = FindWindowEx(SnapHandle, 0&, "edit", vbNullString)
Me.Text = SnapHandle.ToInt32.ToString
If Not SnapHandle2 = 0 Then
Dim href2 As New HandleRef(Me, SnapHandle2)
cds.lpData = strMessage
cds.cbData = cds.lpData.Length + 1
Dim I As IntPtr = SendMessage(href2, WM_SETTEXT, 0&, cds.lpData)
End If
End If
GC.KeepAlive(Me)
End Sub
Private Sub sndButton_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles sndButton.Click
SendToApplication(Me.searchTxtBox.Text, Me.msgTxtBox.Text)
End Sub
End Class
Yes, but you are using WM_SETTEXT rather than WM_COPYDATA in your code.
The code is a bit of a mess but, its hours of trail and error...
Ive used a similar approach to set or change the Notepad title window caption with WM_SETTEXT... but the end application requires and listens to a WM_COPYDATA. Ive included what i got so far... It contains a lot of junk code an unused sections... Just cant seem to figure this out. :(
vb Code:
Are you sure your parameters are correct (Notepad is waiting for 1 as dwData etc)? The Message returns false no matter what I try and I tried ways that are supposed to work.
Here is a C# example that uses WM_COPYDATA. It sends the message but Notepad returns False.
Another code I changed to work with Notepad fails too:Code:Dim notepadHWND As IntPtr
Declare Function FindWindow Lib "user32" Alias "FindWindowA" _
(ByVal ClassName As String, ByVal WindowName As String) As IntPtr
Private Declare Auto Function SendMessage Lib "user32" ( _
ByVal hwnd As IntPtr, _
ByVal wMsg As Integer, _
ByVal wParam As Integer, _
ByRef lParam As COPYDATASTRUCT _
) As Integer
<System.Runtime.InteropServices.StructLayout(System.Runtime.InteropServices.LayoutKind.Sequential)> _
Private Structure COPYDATASTRUCT
Public dwData As Integer
Public cbData As Integer
Public lpData As IntPtr
End Structure
Private Const WM_COPYDATA As Integer = &H4A
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
'get the handle of Notepad's window
notepadHWND = FindWindow("Notepad", "z123.txt - Notepad")
Send("HI")
End Sub
Public Function Send(ByVal obj As Object) As Integer
' Try to do a binary serialization on obj.
' This will throw and exception if the object to
' be passed isn't serializable.
' Try to do a binary serialization on obj.
' This will throw and exception if the object to
' be passed isn't serializable.
Dim b As System.Runtime.Serialization.Formatters.Binary.BinaryFormatter = _
New System.Runtime.Serialization.Formatters.Binary.BinaryFormatter()
Dim stream As System.IO.MemoryStream = New System.IO.MemoryStream()
b.Serialize(stream, obj)
stream.Flush()
' Now move the data into a pointer so we can send
' it using WM_COPYDATA:
' Get the length of the data:
Dim dataSize As Integer = CInt(stream.Length)
If (dataSize > 0) Then
' This isn't very efficient if your data is very large.
' First we copy to a byte array, then copy to a CoTask
' Mem object... And when we use WM_COPYDATA windows will
' make yet another copy! But if you're talking about 4K
' or less of data then it doesn't really matter.
Dim data(dataSize) As Byte
stream.Seek(0, System.IO.SeekOrigin.Begin)
stream.Read(data, 0, dataSize)
Dim ptrData As IntPtr = System.Runtime.InteropServices.Marshal.AllocCoTaskMem(dataSize)
System.Runtime.InteropServices.Marshal.Copy(data, 0, ptrData, dataSize)
Dim cds As COPYDATASTRUCT = New COPYDATASTRUCT()
cds.cbData = dataSize
cds.dwData = 1
cds.lpData = ptrData
Dim res As Integer = SendMessage(notepadHWND, WM_COPYDATA, Me.Handle.ToInt32(), cds)
' Clear up the data:
System.Runtime.InteropServices.Marshal.FreeCoTaskMem(ptrData)
End If
stream.Close()
End Function
Well actually im trying to send to AutoCAD. Ive made some sort of successful atempts today although it just sends gibberish characters and im assuming its a unicode problem... Its just that my old VB6 code allows me to send to Notepad without a problem.
I get this below when sending msg = "asdf" as a string.
>Unknown command "F獡晤". Press F1 for help.
>Command: f獡晤
>Unknown command "F獡晤". Press F1 for help.
>Command: f獡晤
Cant believe this.
/A
Currently im playing with the code similar to below, which atleast sends something to AutoCAD - but as i mentioned, incorrect characters.
vb Code:
If it sends something, then it is working :)
Try Encoding.Default here and there instead of ASCII & Unicode.
Ill give it a try, problem is finding the correct value for .cbData
DataStruct.cbData = (Encoding.Unicode.GetByteCount(strMessage) + 1)
and also, the behavior can be kinda sluggish.. i.e. it doesnt work 10 time out of 10, but maybe 8-9 times out of 10.
/A
The Code below does the best job in sending data to my application, however im having issues determining the size of the string and again, everything gets screambled into Chineese unicode characters. :(
VB Code:
How about...
vb.net Code:
------------------------------------------------------------------------------------------
C# sample below is what I use for SendMessage
[DllImport("user32.dll", EntryPoint = "SendMessage", CharSet = CharSet.Auto)]
internal static extern int SendMessage(IntPtr hWnd, int msg, IntPtr wParam, ref COPYDATASTRUCT lParam);
internal struct COPYDATASTRUCT : IDisposable
{
public int dwData;
public int cbData;
public IntPtr lpData;
public void Dispose()
{
lpData = IntPtr.Zero;
}
}
COPYDATASTRUCT cds = new COPYDATASTRUCT();
string data = strMessage + "\0";
cds.cbData = data.Length * Marshal.SystemDefaultCharSize;
cds.lpData = Marshal.StringToCoTaskMemAuto(data);
SendMessage(hwnd_autocad, WM_COPYDATA, IntPtr.Zero, ref cds);
Marshal.FreeCoTaskMem(cds.lpData);
cds.Dispose();
Holy Cow! A problem i believed to be unsolvable is now solved...
With your suggestion plus changing below actually did the trick!
Code:DataStruct.dwData = 1
Your the man! Im eternally greatful! :thumb:
Code:Just posting the finished working code as i got it..
Private Declare Auto Function SendMessage Lib "user32" _
(ByVal hWnd As IntPtr, _
ByVal Msg As Integer, _
ByVal wParam As IntPtr, _
ByRef lParam As COPYDATASTRUCT) As Boolean
Public Const WM_COPYDATA As Integer = &H4A
<StructLayout(LayoutKind.Sequential)> _
Structure COPYDATASTRUCT
Dim dwData As Long
Dim cbData As Long
Dim lpData As IntPtr
End Structure
Public Sub SendToCommandPrompt(ByVal strMessage As String)
Dim DataStruct As New COPYDATASTRUCT
strMessage = strMessage & Chr(0) 'Null terminated
DataStruct.dwData = 1
DataStruct.cbData = strMessage.Length * Marshal.SystemDefaultCharSize
DataStruct.lpData = Marshal.StringToCoTaskMemAuto(strMessage)
SendMessage(hwnd_autocad, WM_COPYDATA, 0, DataStruct)
Marshal.FreeCoTaskMem(DataStruct.lpData)
End Sub