I have a project to scan some QR-code or bar-code with camera on windows mobile. (phone x01t)
Programing in C++ and using DirectShow.
Tired to change focus with IAMCameraControl interface, but return the error like "...request is not supported".
Are there any way else?
Most (if not all) Windows Mobile phones I've used so far used custom camera drivers, which means OEMs decide which functionalities to implement/support. IAMCameraControl is most likely not one of them.
However, you might want to look for OEM-specific SDKs. For instance, Samsung provides custom APIs enabling to change such parameters as camera focus or ISO. Maybe such APIs exist for your device.