propertyinfo.getvalue(null, null) advantage null

i have category stationary open ability called "info".
via tact i wish properties value, i call:

propertyinfo pi mytype.getproperty("info");
string info = (string) pi.getvalue(null, null);

this works glorious enlarged ability form string. nonetheless indeed ability form iplugininfo plugininfo form (implementing iplugininfo) instatiated returned info properties accessor, this:

public stationary iplugininfo plugininfo
{
    
    {
        iplugininfo info = new plugininfo();
        info.name = "pluginname";
        info.version = "pluginversion";
        relapse info;
    }
}

like i call:

iplugininfo info = pi.getvalue(null, null) iplugininfo;

info always null, whiel propertyinfo pi still valid. am i blank something apparent here?