C#获取运行程序的进程ID

[DllImport("User32.dll", CharSet = CharSet.Auto)]
public static extern int GetWindowThreadProcessId(IntPtr hwnd, out int ID);

[DllImport("user32.dll", EntryPoint = "FindWindow")]
private extern static IntPtr FindWindow(string lpClassName, string lpWindowName);

static void Main(string[] args)
{
IntPtr hwnd = FindWindow(null, "计算器");
if (hwnd != IntPtr.Zero)
{
int calcID;
//获取进程ID
GetWindowThreadProcessId(hwnd, out calcID);
}
}