Enabling/Disabling Property in PropertyGrid control at runtime.

When you create property in a class you can able to define attribute for that property Like [ReadOnly(True)] to make that property as read only, but i wanted make property as read only at run time. for instance, if property B's value is 1 then property A should be disable some thing like that.....

if some one know about this, please send across us, it would be gr8 help...

thanks in advance.