Question

我试图将gridView绑定到Windows应用商店应用中的ObservableCollection。我的问题是我得到的数据，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，但我已经看了好几天这个代码而无法弄明白该字符串看起来像它的工作，这意味着如果我有2个文本框链接到ValveName字符串设置字符串并获取数据，但它看起来不适用于小数，他们在启动时获取数据，但如果您在文本框似乎不会影响变量

Answer 1

正确的XAML应该看起来像

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

而不是

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

修改旁注：

此代码不是线程安全的。在this.PropertyChanged != null和this.PropertyChanged之间，另一个帖子可以取消订阅，PropertyChanged会变为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)); } }

这个线程现在是安全的

对于未来的读者：使用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＆＃34; Null Propagation Operator＆＃34;运营商。

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

无法从Xaml到ObservableCollection工作获得双向绑定

1 个答案: