How to use this WndProc in Windows Forms application?

Question

Please guide me how to use this WndProc in Windows Forms application:

private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{
    if (msg == NativeCalls.APIAttach && (uint)lParam == NativeCalls.SKYPECONTROLAPI_ATTACH_SUCCESS)
    {
        // Get the current handle to the Skype window
        NativeCalls.HWND_BROADCAST = wParam;
        handled = true;
        return new IntPtr(1);
    }

    // Skype sends our program messages using WM_COPYDATA. the data is in lParam
    if (msg == NativeCalls.WM_COPYDATA && wParam == NativeCalls.HWND_BROADCAST)
    {
        COPYDATASTRUCT data = (COPYDATASTRUCT)Marshal.PtrToStructure(lParam, typeof(COPYDATASTRUCT));
        StatusTextBox.AppendText(data.lpData + Environment.NewLine);

        // Check for connection
        if (data.lpData.IndexOf("CONNSTATUS ONLINE") > -1)
            ConnectButton.IsEnabled = false;

        // Check for calls
        IsCallInProgress(data.lpData);
        handled = true;
        return new IntPtr(1);
    }

    return IntPtr.Zero;
}

I have seen people use the above code in this way in WPF like

protected override void OnSourceInitialized(EventArgs e)
{
    base.OnSourceInitialized(e);

    // Attach WndProc
    HwndSource source = PresentationSource.FromVisual(this) as HwndSource;
    source.AddHook(WndProc);
}

[Here is an example](http://msdn.microsoft.com/en-us/library/system.windows.forms.control.wndproc%28v=vs.110%29.aspx) — Sriram Sakthivel, Apr 22 '14 at 12:56

Elvedin Hamzagic · Answer 1 · 2014-04-23T15:06:57.130

4

The prototype for WndProc in C# is:

protected virtual void WndProc(ref Message m)

So, you need to override this procedure in your class, assumed that it's derived from Control.

protected override void WndProc(ref Message m)
{
    Boolean handled = false; m.Result = IntPtr.Zero;
    if (m.Msg == NativeCalls.APIAttach && (uint)m.Param == NativeCalls.SKYPECONTROLAPI_ATTACH_SUCCESS)
    {
        // Get the current handle to the Skype window
        NativeCalls.HWND_BROADCAST = m.WParam;
        handled = true;
        m.Result = new IntPtr(1);
    }

    // Skype sends our program messages using WM_COPYDATA. the data is in lParam
    if (m.Msg == NativeCalls.WM_COPYDATA && m.WParam == NativeCalls.HWND_BROADCAST)
    {
        COPYDATASTRUCT data = (COPYDATASTRUCT)Marshal.PtrToStructure(m.LParam, typeof(COPYDATASTRUCT));
        StatusTextBox.AppendText(data.lpData + Environment.NewLine);

        // Check for connection
        if (data.lpData.IndexOf("CONNSTATUS ONLINE") > -1)
            ConnectButton.IsEnabled = false;

        // Check for calls
        IsCallInProgress(data.lpData);
        handled = true;
        m.Result = new IntPtr(1);
    }

    if (handled) DefWndProc(ref m); else base.WndProc(ref m);
}

edited Apr 23 '14 at 15:06

answered Apr 22 '14 at 12:54

Elvedin Hamzagic

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thanks for your answer but i just do not understand why controls never come into second if block when i am debugging? can u tell me the reason. thanks – Thomas Apr 23 '14 at 12:39
Sorry, I edited my post. The problem was that `m.Result` is set to zero always at the bottom of the function. Setting it to zero at the beginning will solve this issue, and maybe also your problem. – Elvedin Hamzagic Apr 23 '14 at 15:10
still the same problem exist. – Thomas Apr 24 '14 at 08:19
Maybe you have some problem with the Skype, not `WndProc`. Can you put breakpoint and check for incoming messages? Do you receive normal window messages? – Elvedin Hamzagic Apr 24 '14 at 13:58
i guess no because i develop my application following a wpf based apps which also capture skype sound and save to file....that works great. my application is not working only. i guess i am missing something or there is some mistake in my code that is why problem occur. – Thomas Apr 25 '14 at 06:37
can u plzz download my apps from this url and check at your end if possible. here is the url and download the SkypeCallTest.zip file from this url... https://onedrive.live.com/#cid=C4A6F16F34D7540A&id=C4A6F16F34D7540A!126 – Thomas Apr 25 '14 at 06:39

score 4 · Answer 2 · answered Apr 22 '14 at 13:12

You can use Application.AddMessageFilter Method.

[SecurityPermission(SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.UnmanagedCode)]
public class TestMessageFilter : IMessageFilter
{
    public bool PreFilterMessage(ref Message m)
    {
        // Blocks all the messages relating to the left mouse button. 
        if (m.Msg >= 513 && m.Msg <= 515)
        {
            Console.WriteLine("Processing the messages : " + m.Msg);
            return true;
        }
        return false;
    }
}

what is IMessageFilter and what it does? why u refer it to me to use it? — Thomas, Apr 23 '14 at 12:40

How to use this WndProc in Windows Forms application?

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