如何以可视格式约束告诉tableviewcell类标签名称？

Question

这是我在下面给出的代码：

 NSDictionary *viewsDictionary =   NSDictionaryOfVariableBindings(cell.lblname);
    NSLog(@"%@",viewsDictionary);
   NSArray *constra= [NSLayoutConstraint constraintsWithVisualFormat:@"|-10-[cell.lblname]-10-|" options:NSLayoutFormatAlignAllBaseline metrics:nil views:viewsDictionary];
    //Work through the array of constraints, applying each to the superview
    for (int i = 0; i<constra.count; i++) {
        [cell.contentView addConstraint:constra[i]];
    }

这就是我得到的

2015-12-14 16:23:34.846 hello[2354:102290] {
    "cell.lblname" = "<UILabel: 0x7fd6a1cb7a80; frame = (0 0; 318 40); userInteractionEnabled = NO; layer = <_UILabelLayer: 0x7fd6a1cf4610>>";
}
2015-12-14 16:23:34.898 hello[2354:102290] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Unable to parse constraint format: 
cell is not a key in the views dictionary. 
|-10-[cell.lblname]-10-| 
          ^'

如何解决这个问题对我有帮助，我是视觉约束的新手....

Answer 1

NSDictionary *viewsDictionary = {@"lblname": self.lblname};
NSArray *constraints = [NSLayoutConstraint constraintsWithVisualFormat:@"|-10-[lblname]-10-|" options:NSLayoutFormatAlignAllBaseline metrics:nil views:viewsDictionary];
[cell.contentView addConstraints:constraints];