How to read a windows message posted by another application

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  • Start date Start date
G

Guest

Hi,
I want to post a windows message from one application and read it in another
application.

I am using the below code to post a message to a form but i am not able to
read the message in the receiving form in another application.

IntPtr hWnd;
hWnd = FindWindow(null, "MsgWindow");
int i = PostMessage(hWnd, 5000, 5000, 5000);
if (i == 0)
MessageBox.Show("Window not found!");

[DllImport("coredll.dll")]
public extern static int SendMessage(IntPtr hwnd, uint msg, uint wParam,
uint lParam);
[DllImport("coredll.dll")]
public extern static int PostMessage(IntPtr hwnd, uint msg, uint wParam,
uint lParam);
[DllImport("coredll.dll", EntryPoint = "FindWindowW", CharSet =
CharSet.Unicode)]
public static extern IntPtr FindWindow(String strClass, String strWindowName);

Can some one tell me how that can be done and any sample code showing how it
can be done.

Thanks,
Murthy
 
Hi,

you can override the WndProc procedure and catch the message you
want :

protected override void WndProc(ref Message msg)
{
switch(msg.Msg)
{
case YOUR_MSG:
break;


}

// call the base class WndProc for default message handling
base.WndProc(ref msg);
}


}


BR


Fabien Decret
Windows Embedded Consultant

ADENEO (ADESET)
http://www.adeneo.adetelgroup.com/



Murthy a écrit :
 
Where's the receiving end code? Having just a send is like having a phone
call with one phone - not too useful.
 
Hi,
I tried the following code in the receiving form.
But it is not receiving any message.
i have put a break point in wndproc but the control is not coming there.
In form load i created an instance of myMessageWindowClass....
But this is not working what is it that i am missing...

public class myMessageWindowClass : MessageWindow
{
// Assign integers to messages.
// Note that custom Window messages are after WM_USER = 0x400.
public const int WM_BOXUPDATE = 0x0401;
public const int WM_PNLUPDATE = 0x0402;


// Create an instance of the form.
MsgWindow updateform;

// Save reference to the form so it can
// be notified when messages are received.
public myMessageWindowClass(MsgWindow updateform)
{
this.updateform = updateform;
}

// Override the default WndProc behavior to examine messages.
protected override void WndProc(ref Message msg)
{
switch (msg.Msg)
{
}

// Call the base class WndProc for default message handling.
base.WndProc(ref msg);
}
}

Can someone give me a sample code that will receive any message posted to it
from another application.

Thanks in Advance,
Murthy


Where's the receiving end code? Having just a send is like having a phone
call with one phone - not too useful.


--
Chris Tacke
OpenNETCF Consulting
Managed Code in the Embedded World
www.opennetcf.com
--


Murthy said:
Hi,
I want to post a windows message from one application and read it in
another
application.

I am using the below code to post a message to a form but i am not able to
read the message in the receiving form in another application.

IntPtr hWnd;
hWnd = FindWindow(null, "MsgWindow");
int i = PostMessage(hWnd, 5000, 5000, 5000);
if (i == 0)
MessageBox.Show("Window not found!");

[DllImport("coredll.dll")]
public extern static int SendMessage(IntPtr hwnd, uint msg, uint wParam,
uint lParam);
[DllImport("coredll.dll")]
public extern static int PostMessage(IntPtr hwnd, uint msg, uint wParam,
uint lParam);
[DllImport("coredll.dll", EntryPoint = "FindWindowW", CharSet =
CharSet.Unicode)]
public static extern IntPtr FindWindow(String strClass, String
strWindowName);

Can some one tell me how that can be done and any sample code showing how
it
can be done.

Thanks,
Murthy
Click to expand...
Click to expand...
 
Is FindWindow succeeding? Is the handle it's finding valid and the right
handle for your MessageWindow? Rather than asking for a solution, you'll
learn a lot more by figuring out why your code is failing.


--
Chris Tacke
OpenNETCF Consulting
Managed Code in the Embedded World
www.opennetcf.com
--


Murthy said:
Hi,
I tried the following code in the receiving form.
But it is not receiving any message.
i have put a break point in wndproc but the control is not coming there.
In form load i created an instance of myMessageWindowClass....
But this is not working what is it that i am missing...

public class myMessageWindowClass : MessageWindow
{
// Assign integers to messages.
// Note that custom Window messages are after WM_USER = 0x400.
public const int WM_BOXUPDATE = 0x0401;
public const int WM_PNLUPDATE = 0x0402;


// Create an instance of the form.
MsgWindow updateform;

// Save reference to the form so it can
// be notified when messages are received.
public myMessageWindowClass(MsgWindow updateform)
{
this.updateform = updateform;
}

// Override the default WndProc behavior to examine messages.
protected override void WndProc(ref Message msg)
{
switch (msg.Msg)
{
}

// Call the base class WndProc for default message handling.
base.WndProc(ref msg);
}
}

Can someone give me a sample code that will receive any message posted to
it
from another application.

Thanks in Advance,
Murthy


Where's the receiving end code? Having just a send is like having a
phone
call with one phone - not too useful.


--
Chris Tacke
OpenNETCF Consulting
Managed Code in the Embedded World
www.opennetcf.com
--


Murthy said:
Hi,
I want to post a windows message from one application and read it in
another
application.

I am using the below code to post a message to a form but i am not able
to
read the message in the receiving form in another application.

IntPtr hWnd;
hWnd = FindWindow(null, "MsgWindow");
int i = PostMessage(hWnd, 5000, 5000, 5000);
if (i == 0)
MessageBox.Show("Window not found!");

[DllImport("coredll.dll")]
public extern static int SendMessage(IntPtr hwnd, uint msg, uint
wParam,
uint lParam);
[DllImport("coredll.dll")]
public extern static int PostMessage(IntPtr hwnd, uint msg, uint
wParam,
uint lParam);
[DllImport("coredll.dll", EntryPoint = "FindWindowW", CharSet =
CharSet.Unicode)]
public static extern IntPtr FindWindow(String strClass, String
strWindowName);

Can some one tell me how that can be done and any sample code showing
how
it
can be done.

Thanks,
Murthy
Click to expand...
Click to expand...
Click to expand...
 
Hi,
Sorry for the delay...I was out of town....

Yes the FindWindow is succeeding it is even returning an window handle and
is also posing a windows message. But i am not able to read it.
I even put a break point at WndProc ...It is not even receiving the OS
messages....

I tried to figure it out....also googled but could not find a solution.

Thanks in Advance,
Murthy

Is FindWindow succeeding? Is the handle it's finding valid and the right
handle for your MessageWindow? Rather than asking for a solution, you'll
learn a lot more by figuring out why your code is failing.


--
Chris Tacke
OpenNETCF Consulting
Managed Code in the Embedded World
www.opennetcf.com
--


Murthy said:
Hi,
I tried the following code in the receiving form.
But it is not receiving any message.
i have put a break point in wndproc but the control is not coming there.
In form load i created an instance of myMessageWindowClass....
But this is not working what is it that i am missing...

public class myMessageWindowClass : MessageWindow
{
// Assign integers to messages.
// Note that custom Window messages are after WM_USER = 0x400.
public const int WM_BOXUPDATE = 0x0401;
public const int WM_PNLUPDATE = 0x0402;


// Create an instance of the form.
MsgWindow updateform;

// Save reference to the form so it can
// be notified when messages are received.
public myMessageWindowClass(MsgWindow updateform)
{
this.updateform = updateform;
}

// Override the default WndProc behavior to examine messages.
protected override void WndProc(ref Message msg)
{
switch (msg.Msg)
{
}

// Call the base class WndProc for default message handling.
base.WndProc(ref msg);
}
}

Can someone give me a sample code that will receive any message posted to
it
from another application.

Thanks in Advance,
Murthy


Where's the receiving end code? Having just a send is like having a
phone
call with one phone - not too useful.


--
Chris Tacke
OpenNETCF Consulting
Managed Code in the Embedded World
www.opennetcf.com
--


Hi,
I want to post a windows message from one application and read it in
another
application.

I am using the below code to post a message to a form but i am not able
to
read the message in the receiving form in another application.

IntPtr hWnd;
hWnd = FindWindow(null, "MsgWindow");
int i = PostMessage(hWnd, 5000, 5000, 5000);
if (i == 0)
MessageBox.Show("Window not found!");

[DllImport("coredll.dll")]
public extern static int SendMessage(IntPtr hwnd, uint msg, uint
wParam,
uint lParam);
[DllImport("coredll.dll")]
public extern static int PostMessage(IntPtr hwnd, uint msg, uint
wParam,
uint lParam);
[DllImport("coredll.dll", EntryPoint = "FindWindowW", CharSet =
CharSet.Unicode)]
public static extern IntPtr FindWindow(String strClass, String
strWindowName);

Can some one tell me how that can be done and any sample code showing
how
it
can be done.

Thanks,
Murthy
Click to expand...
Click to expand...
Click to expand...
 
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