how to send url in FB

- (void)postToWall {
FBStream开发者_开发百科Dialog* dialog = [[[FBStreamDialog alloc] init] autorelease];
    dialog.userMessagePrompt = @"Enter your message:";

**NSString *strFirstForActionLink** = @"[{\"text\":\"LOCATION!\",\"href\":\"http://maps.google.com/maps/api/staticmap?center=Brooklyn+Bridge,New+York,NY&zoom=14&size=512x512&maptype=roadmap&markers=color:blue|label:S|40.702147,-74.015794&markers=color:green|label:G|40.711614,-74.012318&markers=color:red|color:red|label:C|40.718217,-73.998284&sensor=true\"}]";
NSLog(@"action link url is %@",strFirstForActionLink);

**dialog.actionLinks = @"strFirstForActionLink";**
}

when i am storing this url string into an string variable and then passing this variable it is creating problem..... pls suggest me