C＃中类似于Keylogger的应用程序，用于记录应用程序开始和结束的时间戳

Question

My main goal is to record the "total time" a user spends on an application. I want to create a background agent in Windows that would be installed on a client PC. This agent is like a keylogger and sits in the background and records the following:

1. The time-stamp when the user "starts" a specific application.
2. Idle time vs active time spent on the application.
3. The time-stamp when the user "ends" a specific application.

My challenges are:

1. How to create a background agent.
2. How to record when the user starts and ends an application.

Any help would be deeply appreciated.

Answer 1

I've writen an Keylogger API in C# that can hook any key pressed by the user and mouse clicks. When one of these events occurs the API returns a callback containing an object that says which key was pressed and WHAT SCREEN THE USER WAS. The same for the mouse click, in wicht it returns where the user have clicked and WHAT SCREEN THE FOCUS WAS IN THAT MOMENT.

In my API this is the method that I use to get the focused screen, you can adapt for your needs:

private static string CurrentWindowTitle()
{
    int hwnd = GetForegroundWindow();
    StringBuilder title = new StringBuilder(1024);

    int textLength = GetWindowText(hwnd, title, title.Capacity);
    if ((textLength <= 0) || (textLength > title.Length))
        return "[Unknown]";

    return $"[{title}]";
}

The methods GetForegroundWindow() and GetWindowText() are just methods of the User32.dll:

[DllImport("User32.dll")]
internal static extern int GetForegroundWindow();

[DllImport("User32.dll")]
internal static extern int GetWindowText(int hwnd, StringBuilder s, int nMaxCount);

The source code of the API that I've mentioned can be foud here