在一个label中显示多行，自动换行

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];

//该代码片段来自于: http://www.sharejs.com/codes/objectc/2000