无法获得从 Xaml 到 ObservableCollection 工作的双向绑定

Question

我正在尝试将 gridView 绑定到 Windows Store 应用程序中的 ObservableCollection。我的问题是我得到了数据，但设置似乎不起作用

public class ValveData : INotifyPropertyChanged
{
    private string valveName;
    private decimal waterMl;
    private decimal waterEc;
    private decimal waterPh;


    public string ValveName 
    {
        get { return this.valveName; }
        set
        {
            this.valveName = value;
            this.OnPropertyChanged("ValveName");
        }
    }

    public decimal WaterMl
    {
        get { return this.waterMl; }
        set
        {
            this.waterMl = value;
            this.OnPropertyChanged("WaterMl");
        }
    }

    public decimal WaterEc
    {
        get { return this.waterEc; }
        set
        {
            this.waterEc = value;
            this.OnPropertyChanged("WaterEc"); 
        }
    }

    public decimal WaterPh
    {
        get { return this.waterPh; }
        set
        {
            this.waterPh = value;
            this.OnPropertyChanged("WaterPh");
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

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

public class ValveDataCollection : ObservableCollection<ValveData>
{
    public ValveDataCollection() : base()
    {
        Add(new ValveData { ValveName = "Valve 1", WaterMl = 100, WaterEc = 3, WaterPh = 5 });
        Add(new ValveData { ValveName = "Valve 2" });
        Add(new ValveData { ValveName = "Valve 3" });
        Add(new ValveData { ValveName = "Valve 4" });
    }
}

这是我的 Xaml

<data:ValveDataCollection x:Key="ValvesData"/>

<GridView x:Name="gw1" Grid.Row="2" ItemsSource="{StaticResource ValvesData}">
        <GridView.ItemTemplate>
            <DataTemplate>
                <StackPanel>
                    <TextBox Text="{Binding ValveName, Mode=TwoWay}"/>
                    <TextBox Text="{Binding WaterMl, Mode=TwoWay}"/>
                    <TextBox Text="{Binding WaterEc, Mode=TwoWay}"/>
                    <TextBox Text="{Binding WaterPh, Mode=TwoWay}"/>
                </StackPanel>
            </DataTemplate>
        </GridView.ItemTemplate>
</GridView>

我确定我遗漏了一些东西，但我已经查看这段代码好几天了，还是想不通该字符串看起来有效，这意味着如果我有 2 个文本框链接到 ValveName 字符串，则设置字符串并获取数据，但它看起来不适用于小数，它们在启动时获取数据，但如果您在文本框它似乎不影响变量

Answer 1

正确的 XAML 应该是

<TextBox Text="{Binding ValveName, Mode=TwoWay}"/>

而不是

<TextBox Text="{Binding ValveName}, Mode=TwoWay"/>

编辑旁注：

此代码不是线程安全的。在 this.PropertyChanged != null 和 this.PropertyChanged 之间，另一个线程可能取消订阅并且 PropertyChanged 变为 null。

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

始终使用事件处理程序的本地副本！

public void OnPropertyChanged(string propertyName)
{
    var handler = this.PropertyChanged;
    if (handler != null)
    {
        handler(this, new PropertyChangedEventArgs(propertyName));
    }
}

这个现在是线程安全的

对于未来的读者：对于 C# 6.0 (Visual Studio 2015)，您还可以使用以下版本，该版本更短和线程安全，使用新的 "Null Propagation Operator" 运算符。

public void OnPropertyChanged(string propertyName)
{
    this.PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}

无法获得从 Xaml 到 ObservableCollection 工作的双向绑定

Cant get twoWay Binding from Xaml to ObservableCollection Working

c#

binding

inotifypropertychanged

winrt-xaml

windows-store-apps