How do I detect a Lock This Computer command from a WPF application?
When you handle the Microsoft.Win32.SystemEvents.SessionSwitch event (which it sounds like you're already doing to detect logout), check to see if the Reason is SessionSwitchReason.SessionLock:
using Microsoft.Win32; // ... // Somewhere in your startup, add your event handler: SystemEvents.SessionSwitch += new SessionSwitchEventHandler(SystemEvents_SessionSwitch); // ... void SystemEvents_SessionSwitch(object sender, SessionSwitchEventArgs e) { switch(e.Reason) { // ... case SessionSwitchReason.SessionLock: // Do whatever you need to do for a lock // ... break; case SessionSwitchReason.SessionUnlock: // Do whatever you need to do for an unlock // ... break; // ... } }