This message is posted to the window with the input focus when the function TranslateMessage transforms a key down message.
The character code for the message.
Key stroke flags.
|Bits 0-15||The typematic repeat count for the key.|
|Bits 16-23||Hardware dependent scan code for the key.|
|Bit 24||Extended key flag.|
|Bit 29||Context code. This bit is set if the alt key was depressed and clear otherwise.|
|Bit 30||Previous key state. This bit is set if the key was depressed prior to the message being sent and clear otherwise.|
|Bit 31||Transition state. This bit is clear if the key is being depressed and set if it is being released.|
If the window processes this message, it should return zero.
The extended keys (bit 24) are:
The information in the high-order part of Parameter2 is for the most recent key down transition - prior to the generation of this message. In general, this information is not that useful because there is not a 1-to-1 correspondence between keys being pressed and character messages being generated.