尽管 INotifyPropertyChanged 已实现，但 ObservableCollection 未更新答案

【问题标题】：ObservableCollection not updating though I INotifyPropertyChanged is implemented尽管 INotifyPropertyChanged 已实现，但 ObservableCollection 未更新
【发布时间】：2019-08-18 03:03:55
【问题描述】：

我需要在 DataGrid 中显示一组从外部源接收的位状态。为此，我使用这样的 ObservableCollection

public class UpdateIO : INotifyPropertyChanged

public static ObservableCollection<IObitDetails> PlcCommonOutputs = new ObservableCollection<IObitDetails>();

我的 IObitDetails 类是

    public class IObitDetails : INotifyPropertyChanged
    {
        bool _bitValue;
        public string BitGroup { get; set; }
        public string BitText { get; set; }
        public short CIOaddress { get; set; }
        public short BitPosition { get; set; }
        public bool BitValue
        {
            get { return _bitValue; }
            set { SetField(ref _bitValue, value); }
        }
        public event PropertyChangedEventHandler PropertyChanged;
        protected void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
        protected bool SetField<T>(ref T field, T value,
        [CallerMemberName] string propertyName = null)
        {
            if (EqualityComparer<T>.Default.Equals(field, value))
                return false;
            field = value;
            OnPropertyChanged(propertyName);
            return true;
        }
        public IObitDetails(string bg, bool bv, string bt, short adr, short pos)
        {
            BitGroup = bg;
            BitValue = bv;
            BitText = bt;
            CIOaddress = adr;
            BitPosition = pos;
        }
    }

接下来我创建了集合

PlcCommonOutputs.Add(new IObitDetails("CO", oCommonOpLampRed,"Op. Red", 0x0001, obitCommonOpLampRed));
PlcCommonOutputs.Add(new IObitDetails("CO", oCommonOpLampGreen,"Op. Green", 0x0001, obitCommonOpLampGreen));
PlcCommonOutputs.Add(new IObitDetails("CO", oCommonMuteA,"MuteA", 0x0001, obitCommonMuteA));
PlcCommonOutputs.Add(new IObitDetails("CO", oCommonMuteB,"MuteB", 0x0001, obitCommonMuteB));
...

这里的 BitPosition 声明为：

private const short obitCommonOpLampRed = 0;
private const short obitCommonOpLampGreen = 1;
private const short obitCommonMuteA = 2;
private const short obitCommonMuteB = 3;
...

每个位都是一个属性，当我读取（在轮询线程中）一个端口并存储在 oCommonOutputsPost 中时会修改它：

        private short _oCommonOutputsPort;
        public short oCommonOutputsPort
        {
            get { return _oCommonOutputsPort; }
            set
            {
                SetField(ref _oCommonOutputsPort, value);
                oCommonOpLampRed = (oCommonOutputsPort & (1 << obitCommonOpLampRed)) != 0;
                oCommonOpLampGreen = (oCommonOutputsPort & (1 << obitCommonOpLampGreen)) != 0;
                oCommonMuteA = (oCommonOutputsPort & (1 << obitCommonMuteA)) != 0;
                oCommonMuteB = (oCommonOutputsPort & (1 << obitCommonMuteB)) != 0;
            }
        }

        private bool _oCommonOpLampRed;
        public bool oCommonOpLampRed
        {
            get { return _oCommonOpLampRed; }
            set { SetField(ref _oCommonOpLampRed, value); }
        }
        private bool _oCommonOpLampGreen;
        public bool oCommonOpLampGreen
        {
            get { return _oCommonOpLampGreen; }
            set { SetField(ref _oCommonOpLampGreen, value); }
            }
        }
        private bool _oCommonMuteA;
        public bool oCommonMuteA
        {
            get { return _oCommonMuteA; }
            set { SetField(ref _oCommonMuteA, value); }
        }
        private bool _oCommonMuteB;
        public bool oCommonMuteB
        {
            get { return _oCommonMuteB; }
            set { SetField(ref _oCommonMuteB, value); }
        }
...

每当我读取一个新的端口值时，这些位都会被设置/重置（我看到位属性被正确修改）。但是 ObservableCollection (PlcCommonOutputs) 没有改变。如果我在调试器中手动更改集合中相应的 BitValue，它们会在 UI 中看到（所以我不包括任何 xaml）。有没有办法在不增加代码复杂度的情况下做到这一点？

【问题讨论】：

ObservableCollection 仅在集合更改（例如添加、删除、移动等元素）时触发事件，而不是在单个元素更改时触发。
你可能想看看 BindingList 而不是 ObservableCollection

标签： c# observablecollection

【解决方案1】：

解决此问题的一个简单方法是在您的 setter 中为您想要更新的值提高 propertychanged。这方面的一个例子是：

private bool _oCommonMuteA;
public bool oCommonMuteA
{
    get { return _oCommonMuteA; }
    set 
    { 
        SetField(ref _oCommonMuteA, value); 
        OnPropertyChanged(nameof(oCommonMuteA));
    }
 }

【讨论】：

但是我之前的 SetField 方法中已经有 OnPropertyChanged。