Press button from a handled process

Question

I created a C# application. With this application I want to access a button from another application, which is not made by me. Its process name is uWebCam. This is how it looks:

http://img829.imageshack.us/img829/6606/djq.png

The button that I want to access is located at the bottom of the application, that in the red hexagonal form.
With Spy++ I took all its classes:

How can I find that button and handle it? I tried something like this, but no answer:

Process process = Process.GetProcessesByName("uWebCam")[0];
IntPtr ButtonHandle = FindWindowEx(process.MainWindowHandle, IntPtr.Zero, null, "button1");
SendMessage(ButtonHandle, BM_CLICK, IntPtr.Zero, IntPtr.Zero);

Here are the API functions:

public const int BM_CLICK = 0x00F5;
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr SendMessage(IntPtr hwnd, uint Msg, IntPtr wParam, IntPtr lParam);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);

Vulpes · Answer

That's right Dan. Trying to do it via the Win32 API would not be easy given the variables involved.

Vulpes · Answer

Disappointing :( A couple of other thoughts: 1. Does that particular button have the focus by default or can you TAB to it and then click it by pressing the ENTER key? 2. Are there any command line options which would allow you to launch the application and perform the function of that button automatically?

Vulpes · Answer

It looks like it always shows the details for the main window which suggests to me that the button isn't a 'real' control - it's just drawn on the form! Perhaps that's not altogether surprising given its unusual appearance. If that's the case the application must detect when the form is clicked and if the mouse is over the button drawing at the time take the appropriate action. Trying to click it remotely is not therefore going to be easy. Do you know whether there's a keyboard shortcut which can be used to click the button instead of using the mouse? If there is then you could try forcing input focus onto the app with the SetForegroundWindow function and then use SendKeys.Send to send it the appropriate keystrokes.

Vulpes · Answer

Fire up Spy++ and click on the Find Window tool (window + binoculars icon) in the ToolBar. The Find Window dialog should then open up. Now drag the Find Window tool from the dialog place it over the button you're interested in and press OK on the dialog. The Window Properties window should then show up and under the Class tab you will find the class name for the button to be used in the FindWindowEx function. Notice also that the button's parent may not necessarily be the main window itself but some other window - you can check this from the Windows tab. You may therefore need to call FindWindowEx more than once to get the handle for the parent window before you can get the handle for the button itself.

Dan · Answer

That's how you said ; they use drawn form not controls ; tab doesn't work on any control or something like this on this application. And for command-line I don't think so I will try send them a message. So there only left an option right? To try to find the X-Y Coords but the window can be minimized & maximized & resized...

Dan · Answer

This is an awesome idea with the keyboard shortcut ; EDIT: They really suck! They have shortcuts for all buttons and windows and they doesn't have shortcuts for that 3 buttons ( drawn forms ) which are the most important :\

Dan · Answer

I get an Property Inspector Window: http://img825.imageshack.us/img825/5195/6tev.png

Vulpes · Answer

What happens if you now click the OK button?

Dan · Answer

Thank you very much I did what you said to me but if I put the binocular icon on the button or in another place I get the same result... : http://img443.imageshack.us/img443/9817/ljw.png ( where I put the red arrow that's where I put the binocular icon )