SendKeys to Putty, MobaXterm etc... Without Hardcoding FindWindow(null, "Command Prompt");

Question

C#
Visual Studio 2017
WINFORM

I hope you all are well!

I am developing an application that will send the contents of the Clipboard (string) to any terminal (Putty, MobaXterm, etc...). I found a partial solution. It works well if you hard code the windows you want to receive the text. e.g. I hard coded for the Command Prompt windows, and it works.

 IntPtr wordHandle = FindWindow(null, "Command Prompt");  

What I am trying to figure out is how to do this without hard coding which windows gets the text because I do not know what app the user might use. Is there a way to get the last active windows because if I click on the button on the form the other windows loses its focus.

Credit to sending-key-strokes-to-another-application

Code used:

Any suggestions is appreciated.
Sincerely and regards,

Answer 1

It is not clear what you are asking; you are saying many things and I am not sure if any of the extra stuff is part of the question.

Try the following to get the last active window.

IntPtr lastWindowHandle = GetWindow(Process.GetCurrentProcess().MainWindowHandle, (uint)GetWindow_Cmd.GW_HWNDNEXT);
IntPtr hWndParent = GetParent(lastWindowHandle);
while (!hWndParent.Equals(IntPtr.Zero))
{
    lastWindowHandle = hWndParent;
    hWndParent = GetParent(lastWindowHandle);
}

Then after the loop lastWindowHandle will have the handle of the top-level window of the last active application. You will also need the following.

[DllImport("user32.dll", SetLastError = true)]
static extern IntPtr GetWindow(IntPtr hWnd, uint uCmd);
enum GetWindow_Cmd : uint
{
    GW_HWNDFIRST = 0,
    GW_HWNDLAST = 1,
    GW_HWNDNEXT = 2,
    GW_HWNDPREV = 3,
    GW_OWNER = 4,
    GW_CHILD = 5,
    GW_ENABLEDPOPUP = 6
}
[DllImport("user32.dll", ExactSpelling = true, CharSet = CharSet.Auto)]
public static extern IntPtr GetParent(IntPtr hWnd);

Answer 2

You can use GetForegroundWindow to get the active window.

[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]  
        static extern IntPtr GetForegroundWindow();  
  
        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]  
        static extern int GetWindowText(IntPtr hWnd, StringBuilder text, int count);  
  
        private static string GetCaptionOfActiveWindow()  
        {  
            var strTitle = string.Empty;  
            var handle = GetForegroundWindow();  
            // Obtain the length of the text     
            var intLength = 256;  
            var stringBuilder = new StringBuilder(intLength);  
            if (GetWindowText(handle, stringBuilder, intLength) > 0)  
            {  
                strTitle = stringBuilder.ToString();  
            }  
            return strTitle;  
        }  

Combining these codes with Timer should meet your needs.

You can also consider using SetWinEventHook to monitor EVENT_SYSTEM_FOREGROUND to detect changes in the foreground window. This is an example. I haven't tested it yet, but it should be fine in theory.

asynchronously GetForegroundWindow via SendMessage or something?

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