Question

我试图在一段时间内找到答案。我想要做的是改变与他的＆＃34;父亲＆＃34;相关的ViewController的约束。这是我试图做的，但我收到一个错误：

 partial void BackAction(Foundation.NSObject sender)
 {
   /// My "parent" view controller - the one that presented this view
   UIViewController ApplicationViewController = Application.GetPresentedViewController("ApplicationViewController");
   /// Here I am trying to update the constrains in relation with his father  
   View.AddConstraint(NSLayoutConstraint.Create(ApplicationViewController.View, NSLayoutAttribute.LeftMargin, NSLayoutRelation.Equal, 1, 30));
   /// and also let the view digest the constrains
   View.UpdateConstraints();
 }

当我添加约束时，我收到此错误：

Objective-C exception thrown.  
Name: NSInvalidArgumentException 
Reason: NSLayoutConstraint for <UILayoutContainerView: 0x104903e70; frame = (0 0; 375 812); autoresize = W+H; layer = <CALayer: 0x1c802ff20>>: 
A multiplier of 0 or a nil second item together with a location for the first attribute creates an illegal constraint of a location equal to a constant. 
Location attributes must be specified in pairs.

请帮我看看，谢谢

Answer 1

您需要添加缺少的视图参数。

Create（NSObject，NSLayoutAttribute，NSLayoutRelation，NSObject， NSLayoutAttribute，nfloat，nfloat）

View.AddConstraint(NSLayoutConstraint.Create(ApplicationViewController.View, NSLayoutAttribute.LeftMargin, NSLayoutRelation.Equal,View,NSLayoutAttribute.LeftMargin,1, 30));

更改显示的视图控制器约束

1 个答案: