MvvmCross/Xamarin “This class is not key value coding-compliant for the key” [duplicate]

问题

I know this question has been asked a million times but I'm getting the error trying to follow along with Stuart Lodge's tutorials "N+1 days of MvvmCross", N=11, CollectionView. I'm not following along 100% as I've got another project that I'm editing while watching the tutorials so I'm sure I've just missed something. Here is the full error message:

Foundation.MonoTouchException: Objective-C exception thrown.  
Name: NSUnknownKeyException Reason: [<NSObject 0x796c2460>    
setValue:forUndefinedKey:]: this class is not key value 
coding-compliant for the key MyLabel.

There appears to be a valid outlet for the auto-generate partial class for TestItemView

I don't believe this is a case of adding a control to the xib, then removing it, so that there is a stranded connection. This happens when I delete the xib and start all over again. I have a "FirstView : MvxCollectionViewController" and for the cells I have a "TestItemView : MvxCollectionViewCell" which is a stand-in for the "KittenCollectionCell". I will give the source code for FirstView, TestItemView, and the TestItemView.xib below.

FirstView:

using System.Drawing;
using MvvmCross.Binding.BindingContext;
using MvvmCross.iOS.Views;
using Foundation;
using MvvmCross.Binding.iOS.Views;
using UIKit;

namespace FirstDemo.Core.iOS.Views
{
    [Register("FirstView")]
    public class FirstView : MvxCollectionViewController
    {
        private bool _isInitialized = false;
        public FirstView() : base(new UICollectionViewFlowLayout() {
            ItemSize = new SizeF(240, 400),
            ScrollDirection = UICollectionViewScrollDirection.Horizontal
        })
        {
            _isInitialized = true;
            ViewDidLoad();
        }

        public sealed override void ViewDidLoad()
        {
            if (!_isInitialized)
                return;

            base.ViewDidLoad();
            //var source = new MvxStandardTableViewSource(TestItemsTableView, "TitleText Name;");
            //TestItemsTableView.Source = source;
            CollectionView.RegisterNibForCell(TestItemView.Nib, TestItemView.Key);
            var source = new MvxCollectionViewSource(CollectionView, TestItemView.Key);
            CollectionView.Source = source;

            var set = this.CreateBindingSet<FirstView, Core.ViewModels.FirstViewModel>();
                             set.Bind(source).To(vm => vm.TestItemViewModels);
            set.Apply();
            CollectionView.ReloadData();
          }
    }
}

Here is my hand-coded partial for TestItemView:

using System;
using FirstDemo.Core.ViewModels;
using Foundation;
using MvvmCross.Binding.BindingContext;
using MvvmCross.Binding.iOS.Views;
using UIKit;

namespace FirstDemo.Core.iOS
{
    public partial class TestItemView : MvxCollectionViewCell
    {
        public static readonly UINib Nib = UINib.FromName("TestItemView", NSBundle.MainBundle);
        public static readonly NSString Key = new NSString("TestItemView");

        public TestItemView(IntPtr handle)
            : base(string.Empty /* TODO - this isn't really needed - mvx bug */, handle)
        {
            this.DelayBind(() =>
            {
                var set = this.CreateBindingSet<TestItemView, TestItemViewModel>();
                set.Bind(MyLabel).To(testItem => testItem.Name);
                set.Apply();
            });
        }

        public static TestItemView Create()
        {
            return (TestItemView)Nib.Instantiate(null, null)[0];
        }
    }
}

Here is the auto-generated partial:

// WARNING
//
// This file has been generated automatically by Xamarin Studio from the outlets and
// actions declared in your storyboard file.
// Manual changes to this file will not be maintained.
//
using Foundation;
using System;
using System.CodeDom.Compiler;
using UIKit;

namespace FirstDemo.Core.iOS
{
    [Register ("TestItemView")]
    partial class TestItemView
    {
        [Outlet]
        [GeneratedCode ("iOS Designer", "1.0")]
        UILabel MyLabel { get; set; }

        [Outlet]
        [GeneratedCode ("iOS Designer", "1.0")]
        UIView TestItemInfo { get; set; }

        void ReleaseDesignerOutlets ()
        {
            if (MyLabel != null) {
                MyLabel.Dispose ();
                MyLabel = null;
            }
            if (TestItemInfo != null) {
                TestItemInfo.Dispose ();
                TestItemInfo = null;
            }
        }
    }
}

And finally, the notorious xib for TestItemView:

<document type="com.apple.InterfaceBuilder3.CocoaTouch.XIB" version="3.0" toolsVersion="6211" systemVersion="14A298i" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES"><dependencies><plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="6204"/></dependencies><objects><placeholder placeholderIdentifier="IBFilesOwner" id="-1" userLabel="File's Owner" customClass="TestItemView"><connections><outlet property="MyLabel" destination="28" id="name-outlet-28"/><outlet property="TestItemInfo" destination="1" id="name-outlet-1"/></connections></placeholder><placeholder placeholderIdentifier="IBFirstResponder" id="-2" customClass="UIResponder"/><view contentMode="scaleToFill" id="1"><rect key="frame" x="0.0" y="0.0" width="600" height="600"/><autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/><color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="calibratedWhite"/><subviews><label opaque="NO" clipsSubviews="YES" userInteractionEnabled="NO" contentMode="left" text="Label" lineBreakMode="tailTruncation" minimumFontSize="10" id="28" translatesAutoresizingMaskIntoConstraints="NO" fixedFrame="YES"><rect key="frame" x="235" y="172" width="42" height="21"/><color key="backgroundColor" white="0.0" alpha="0.0" colorSpace="calibratedWhite"/><fontDescription key="fontDescription" type="system" pointSize="17"/><color key="textColor" cocoaTouchSystemColor="darkTextColor"/><nil key="highlightedColor"/></label></subviews><userDefinedRuntimeAttributes><userDefinedRuntimeAttribute keyPath="accessibilityIdentifier" type="string" value="MyTestItem"/></userDefinedRuntimeAttributes></view></objects></document>

If anyone has a clue, I'd appreciate the help because I'm at a complete loss.

Thanks!

回答1:

I am not familier with the swift approach. But in objective-c, you have to manually add outlet object from XIB to code. And when your XIB's view is linked to some older view's address this error will appear. So in objective-c we used to do the below steps.

open you XIB
search for the label with name MyLabel
verify the connection(which object it is linked to)
if needed, remove the outlet linking and add that once again.

来源：https://stackoverflow.com/questions/37364361/mvvmcross-xamarin-this-class-is-not-key-value-coding-compliant-for-the-key

标签

ios

objective-c

mvvmcross