在一个label中显示多行，自动换行

在active.com的开发项目中，遇到一个动态显示detail page的问题。取的数据有的时候多有的时候少，而且还需要自动换行。计算行的高度，text的长度，大小等。EventAddresslabel=[[UILabel alloc]initWithFrame:CGRectMake(starttimelabel.frame.origin.x, starttimelabel.frame.origin.y+distance, 270, 20)];

EventAddresslabel.backgroundColor=[UIColor clearColor];

EventAddresslabel.textColor=[UIColor whiteColor];

EventAddresslabel.font=[UIFont systemFontOfSize:15];

EventAddresslabel.numberOfLines =0; //this is used to determine how many lines this label will have.if =3,it means this label's text will show 3 lines.if =0 ,it means that this label's text will show the line whate it needs.no limit.

EventAddresslabel.lineBreakMode = UILineBreakModeWordWrap;// sys will change the line by word.aslo can be by character for another value.

EventAddresslabel.text=[NSString stringWithFormat:@"%@ %@,%@",cassetInfo.eventAddress,cassetInfo.city,cassetInfo.state];

[uiview addSubview:EventAddresslabel];

CGSize EventAddresslabelsize = [EventAddresslabel.text sizeWithFont:[UIFont systemFontOfSize:15] constrainedToSize:CGSizeMake(285, [EventAddresslabel.text length])lineBreakMode:UILineBreakModeWordWrap];

[EventAddresslabel setFrame:CGRectMake(EventAddresslabel.frame.origin.x,EventAddresslabel.frame.origin.y, 290,EventAddresslabelsize.height+10)];

Description=[[UILabel alloc]initWithFrame:CGRectMake(5,EventAddresslabel.frame.origin.y+EventAddresslabel.frame.size.height, 320, 60)];

DescriptionactivityView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];

DescriptionactivityView.frame = CGRectMake(140.f, EventAddresslabel.frame.origin.y+30, 30.0f,30.0f);

Londinglabel_1=[[UILabel alloc]initWithFrame:CGRectMake(132, Description.frame.origin.y+30, 80,20)];

Labelflag=0;

Description.backgroundColor=[UIColor clearColor];

Description.textColor=[UIColor whiteColor];

Description.font=[UIFont systemFontOfSize:15];

Description.numberOfLines =0;

Description.lineBreakMode = UILineBreakModeWordWrap;

[uiview addSubview:Description];