C # getwindowthreadprocessid usage

Function: This function returns the ID of the process that creates the specified window thread and the process that creates the window. The last one is optional.

Function prototype; DWORD getwindowthreadprocessld (hwnd, lpdword lpdwprocessld );

Parameters:

Hwnd: Window handle.

Lpdwprocessld: the address that receives the 32-bit value of the Process Identity. If this parameter is not null, getwindwthreadprocessld copies the process identifier to the 32-bit value. Otherwise, the process identifier is not copied.

Return Value: the return value is the thread ID of the window to be created.

Use this function in C # To first import the namespace:

Using system. runtime. interopservices;

Then write the code of the API reference and put it into the class.
[Dllimport ("user32.dll", charset = charset. Auto)]
Public static extern int getwindowthreadprocessid (intptr hwnd, out int ID );

This function has two parameters. The first parameter is the window handle obtained by findwindow, and the second parameter is the variable that stores the process ID. For example:

// Obtain the calculator window handle
Intptr hwnd = findwindow (null, "Calculator ");
If (hwnd! = Intptr. Zero)
{
Int calcid;
// Obtain the process ID
Getwindowthreadprocessid (hwnd, out calcid );
MessageBox. Show (calcid. tostring ());
}
Else
{
MessageBox. Show ("No calculator window found ");
}