SendMessage always returns zero
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1
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I am using the User32 SendMessage function to send raw keyboard input to my API.
The function that intercepts the SendMessage call is the WndProc function. I need to receive this data back where SendMessage was called from. I have tried setting the message.Result and saving the SendMessage function to an int, but every time it equals 0. How can I obtain this return data?
Calling the Function
[DllImport("user32.dll")]
public static extern IntPtr SendMessage(IntPtr hWnd, uint wMsg, int wParam, ref Rawkeyboard lParam);
public void SomeFunction(...){
int result = SendMessage(Hook, 0x1230FF, 0, ref lParamKeyboard).ToInt32(); // Send data
Console.WriteLine(result);
}
Responding to the call
protected override void WndProc(ref Message message){
switch (message.Msg){
case 0x1230FF: {
message.Result = (IntPtr)6; // Set result as 6 (just for testing)
}
break;
}
base.WndProc(ref message);
}
c# user32
edited Nov 21 at 5:57
John
10.4k31734
asked Nov 21 at 5:53
SillySam
526
add a comment |
up vote
1
down vote
favorite
I am using the User32 SendMessage function to send raw keyboard input to my API.
The function that intercepts the SendMessage call is the WndProc function. I need to receive this data back where SendMessage was called from. I have tried setting the message.Result and saving the SendMessage function to an int, but every time it equals 0. How can I obtain this return data?
Calling the Function
[DllImport("user32.dll")]
public static extern IntPtr SendMessage(IntPtr hWnd, uint wMsg, int wParam, ref Rawkeyboard lParam);
public void SomeFunction(...){
int result = SendMessage(Hook, 0x1230FF, 0, ref lParamKeyboard).ToInt32(); // Send data
Console.WriteLine(result);
}
Responding to the call
protected override void WndProc(ref Message message){
switch (message.Msg){
case 0x1230FF: {
message.Result = (IntPtr)6; // Set result as 6 (just for testing)
}
break;
}
base.WndProc(ref message);
}
c# user32
edited Nov 21 at 5:57
John
10.4k31734
asked Nov 21 at 5:53
SillySam
526
1
After you setmessage.Result, you then callbase.WndProc(ref message)which will modify the message further. Also, window message numbers go up to 65535. 0x1230ff is out of range.
– Raymond Chen
Nov 21 at 6:33
@RaymondChen I have changed the message number to0x00FFas well as not executingbase.WndProc(ref message)if the case is my message, still not working ;( any other suggestions?
– SillySam
Nov 21 at 7:16
1
Message0x00FFis already defined by the system asWM_INPUT. Class custom messages must be in the range0x0400to0x7FFF. App custom messages must be in the range0x8000to0xBFFF.
– Raymond Chen
Nov 21 at 7:33
1
This isn't broken. Simplest explanation is that you used the wrong window handle. Start VS a second time and use it to debug the app with the WndProc call. Set a breakpoint to verify that code actually runs.
– Hans Passant
Nov 21 at 9:43
add a comment |
up vote
1
down vote
favorite
up vote
1
down vote
favorite
I am using the User32 SendMessage function to send raw keyboard input to my API.
The function that intercepts the SendMessage call is the WndProc function. I need to receive this data back where SendMessage was called from. I have tried setting the message.Result and saving the SendMessage function to an int, but every time it equals 0. How can I obtain this return data?
Calling the Function
[DllImport("user32.dll")]
public static extern IntPtr SendMessage(IntPtr hWnd, uint wMsg, int wParam, ref Rawkeyboard lParam);
public void SomeFunction(...){
int result = SendMessage(Hook, 0x1230FF, 0, ref lParamKeyboard).ToInt32(); // Send data
Console.WriteLine(result);
}
Responding to the call
protected override void WndProc(ref Message message){
switch (message.Msg){
case 0x1230FF: {
message.Result = (IntPtr)6; // Set result as 6 (just for testing)
}
break;
}
base.WndProc(ref message);
}
c# user32
edited Nov 21 at 5:57
John
10.4k31734
asked Nov 21 at 5:53
SillySam
526
I am using the User32 SendMessage function to send raw keyboard input to my API.
The function that intercepts the SendMessage call is the WndProc function. I need to receive this data back where SendMessage was called from. I have tried setting the message.Result and saving the SendMessage function to an int, but every time it equals 0. How can I obtain this return data?
Calling the Function
[DllImport("user32.dll")]
public static extern IntPtr SendMessage(IntPtr hWnd, uint wMsg, int wParam, ref Rawkeyboard lParam);
public void SomeFunction(...){
int result = SendMessage(Hook, 0x1230FF, 0, ref lParamKeyboard).ToInt32(); // Send data
Console.WriteLine(result);
}
Responding to the call
protected override void WndProc(ref Message message){
switch (message.Msg){
case 0x1230FF: {
message.Result = (IntPtr)6; // Set result as 6 (just for testing)
}
break;
}
base.WndProc(ref message);
}
c# user32
c# user32
edited Nov 21 at 5:57
John
10.4k31734
asked Nov 21 at 5:53
SillySam
526
edited Nov 21 at 5:57
John
10.4k31734
asked Nov 21 at 5:53
SillySam
526
edited Nov 21 at 5:57
John
10.4k31734
edited Nov 21 at 5:57
John
10.4k31734
edited Nov 21 at 5:57
John
10.4k31734
10.4k31734
asked Nov 21 at 5:53
SillySam
526
asked Nov 21 at 5:53
SillySam
526
asked Nov 21 at 5:53
SillySam
526
526
1
After you setmessage.Result, you then callbase.WndProc(ref message)which will modify the message further. Also, window message numbers go up to 65535. 0x1230ff is out of range.
– Raymond Chen
Nov 21 at 6:33
@RaymondChen I have changed the message number to0x00FFas well as not executingbase.WndProc(ref message)if the case is my message, still not working ;( any other suggestions?
– SillySam
Nov 21 at 7:16
1
Message0x00FFis already defined by the system asWM_INPUT. Class custom messages must be in the range0x0400to0x7FFF. App custom messages must be in the range0x8000to0xBFFF.
– Raymond Chen
Nov 21 at 7:33
1
This isn't broken. Simplest explanation is that you used the wrong window handle. Start VS a second time and use it to debug the app with the WndProc call. Set a breakpoint to verify that code actually runs.
– Hans Passant
Nov 21 at 9:43
add a comment |
1
After you setmessage.Result, you then callbase.WndProc(ref message)which will modify the message further. Also, window message numbers go up to 65535. 0x1230ff is out of range.
– Raymond Chen
Nov 21 at 6:33
@RaymondChen I have changed the message number to0x00FFas well as not executingbase.WndProc(ref message)if the case is my message, still not working ;( any other suggestions?
– SillySam
Nov 21 at 7:16
1
Message0x00FFis already defined by the system asWM_INPUT. Class custom messages must be in the range0x0400to0x7FFF. App custom messages must be in the range0x8000to0xBFFF.
– Raymond Chen
Nov 21 at 7:33
1
This isn't broken. Simplest explanation is that you used the wrong window handle. Start VS a second time and use it to debug the app with the WndProc call. Set a breakpoint to verify that code actually runs.
– Hans Passant
Nov 21 at 9:43
1
1
After you set
message.Result, you then call base.WndProc(ref message) which will modify the message further. Also, window message numbers go up to 65535. 0x1230ff is out of range.– Raymond Chen
Nov 21 at 6:33
After you set
message.Result, you then call base.WndProc(ref message) which will modify the message further. Also, window message numbers go up to 65535. 0x1230ff is out of range.– Raymond Chen
Nov 21 at 6:33
@RaymondChen I have changed the message number to
0x00FF as well as not executing base.WndProc(ref message) if the case is my message, still not working ;( any other suggestions?– SillySam
Nov 21 at 7:16
@RaymondChen I have changed the message number to
0x00FF as well as not executing base.WndProc(ref message) if the case is my message, still not working ;( any other suggestions?– SillySam
Nov 21 at 7:16
1
1
Message
0x00FF is already defined by the system as WM_INPUT. Class custom messages must be in the range 0x0400 to 0x7FFF. App custom messages must be in the range 0x8000 to 0xBFFF.– Raymond Chen
Nov 21 at 7:33
Message
0x00FF is already defined by the system as WM_INPUT. Class custom messages must be in the range 0x0400 to 0x7FFF. App custom messages must be in the range 0x8000 to 0xBFFF.– Raymond Chen
Nov 21 at 7:33
1
1
This isn't broken. Simplest explanation is that you used the wrong window handle. Start VS a second time and use it to debug the app with the WndProc call. Set a breakpoint to verify that code actually runs.
– Hans Passant
Nov 21 at 9:43
This isn't broken. Simplest explanation is that you used the wrong window handle. Start VS a second time and use it to debug the app with the WndProc call. Set a breakpoint to verify that code actually runs.
– Hans Passant
Nov 21 at 9:43
add a comment |
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1
After you set
message.Result, you then callbase.WndProc(ref message)which will modify the message further. Also, window message numbers go up to 65535. 0x1230ff is out of range.– Raymond Chen
Nov 21 at 6:33
@RaymondChen I have changed the message number to
0x00FFas well as not executingbase.WndProc(ref message)if the case is my message, still not working ;( any other suggestions?– SillySam
Nov 21 at 7:16
1
Message
0x00FFis already defined by the system asWM_INPUT. Class custom messages must be in the range0x0400to0x7FFF. App custom messages must be in the range0x8000to0xBFFF.– Raymond Chen
Nov 21 at 7:33
1
This isn't broken. Simplest explanation is that you used the wrong window handle. Start VS a second time and use it to debug the app with the WndProc call. Set a breakpoint to verify that code actually runs.
– Hans Passant
Nov 21 at 9:43