static public GoBackCmd Ensure(StackConductor <T> holder, ref WeakReference <GoBackCmd> cmdRef)
{
GoBackCmd cmd;
if (cmdRef == null)
{
cmdRef = cmd = new GoBackCmd(holder);
}
else if ((cmd = cmdRef.Target) == null)
{
cmdRef.Target = cmd = new GoBackCmd(holder);
}
return(cmd);
}
public GoBackCmd(StackConductor <T> c)
{
_c = c;
}