But I want to make the two button available at the same time not only change the other one available but the others disable.
ps:I use the SetMouseButtons() call, but it isn't useful.
csRef<iPcMeshSelect> pcms = CEL_QUERY_PROPCLASS_ENT (entity_cam, iPcMeshSelect);
printf("mouse %d!\n",pcms->GetMouseButtons ());
But it print out "mouse 2". But the left mouse button wan't send message, and no effact.
The SetMouseButtons() call will control what buttons have an effect on mesh selection. Check the API docs of iPcMeshSelect.