INotifyPropertyChanged和DataBinding

Question

我正在制作一个测试应用程序来处理CardReader，我有一个带有CardReader状态的枚举和一个带有TextBlock的XAML窗口，我希望当状态改变时，onPropertyChanged用状态的名称更改TextBlock。

下面是我代码的一部分：

public class CardControler : INotifyPropertyChanged
{

    private CardState state;

    public CardState State
    {
        get { return state; }
        set
        {
            if (state != value)
            {
                state = value;
                OnPropertyChanged(state);
            }
        }
    }
public event PropertyChangedEventHandler PropertyChanged;

    protected void OnPropertyChanged(CardState state)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(state.ToString()));
        }

    }

......................................................................

public partial class CardReader : Window
{

    public CardControler control { get; set; }

    public CardReader(int port)
    {

        this.DataContext = control;
        this.port = port;            
        InitializeComponent();
        ScreenWrite(CardState.Initializing);
        Thread thread = new Thread(new ThreadStart(asincControlCreate));
        thread.Start();

    }

在xaml中

<TextBlock Name="Screen" Text="{Binding Path=control.state}></TextBlock>

我希望我能正确地解释我的自我，有人能帮助我。提前感谢

Answer 1

我认为问题在于，您使用的是正在更改的OnPropertyChanged值，而不是实际的属性名称(即(本案中的“国家”)。

protected void OnPropertyChanged(String propertyName)
{
    if (PropertyChanged != null)
    {
        PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
    }
}

我怀疑您还需要更改XAML以绑定到适当的属性(注意，属性名是State而不是state - XAML将区分大小写)：

<TextBlock Name="Screen" Text="{Binding Path=control.State}></TextBlock>

Answer 2

下面的行是不正确的，因为您应该将propertyName作为参数传递而不是state.ToString()

PropertyChanged(this, new PropertyChangedEventArgs(state.ToString()));

因此，您的代码应该类似于：

public CardState State
{
    get { return state; }
    set
    {
        if (state != value)
        {
            state = value;
            OnPropertyChanged("State");
        }
    }
}

public event PropertyChangedEventHandler PropertyChanged;

protected void OnPropertyChanged(string propertyName)
{
    if (PropertyChanged != null)
    {
        PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
    }
}

此外，请记住，xaml是区分大小写的，所以{Binding State}与{Binding state}不一样。

Answer 3

您应该传递更改的属性的名称，而不是其值：

PropertyChanged(this, new PropertyChangedEventArgs("State"));