Question

我正在开发一个C＃项目，其中必须使用WPF，并且在将动态内容绑定到UI时遇到一些问题。

简而言之，我在一个名为NotifyIconResources.xaml的文件中声明了此textBlock：

<TextBlock Name="label_stato" Text="{Binding Source={x:Static Application.Current}, Path=Properties[status]}"/>

它显示了在App.xaml.cs中声明的名为status的字符串属性的值：

public partial class App : Application, INotifyPropertyChanged
{
    private MainWindow mw;

    private TaskbarIcon notifyIcon;

    public event PropertyChangedEventHandler PropertyChanged;

    private string _status;
    private string status
    {
        get
        {
            return _status;
        }
        set
        {
            _status = value;
            NotifyPropertyChanged("status");
        }
    }

    /// <summary>
    /// Triggers a GUI update on a property change
    /// </summary>
    /// <param name="propertyName"></param>
    private void NotifyPropertyChanged(string propertyName = "")
    {
        if (PropertyChanged != null)
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
    }

    protected override void OnStartup(StartupEventArgs e)
    {
        base.OnStartup(e);

        this.Properties["status"] = "Online";

        //create the notifyicon (it's a resource declared in NotifyIconResources.xaml
        ResourceDictionary rd = new ResourceDictionary
        {
            Source = new Uri("/NotifyIconResources.xaml", UriKind.RelativeOrAbsolute)
        };
        notifyIcon = (TaskbarIcon)rd["NotifyIcon"];

        mw = new MainWindow(Environment.GetCommandLineArgs()[1]);
        mw.Show();
    }
}

该属性的值是动态的，其初始值显示在textBlock中，但是对其值的下一次修改不会导致刷新textBlock内容。

NotifyIconResources.xaml在App.xaml中声明：

<Application x:Class="FileSharingOnLAN.App"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:local="clr-namespace:FileSharingOnLAN"
         StartupUri="MainWindow.xaml"
         ShutdownMode="OnExplicitShutdown">
<Application.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="NotifyIconResources.xaml" />
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
</Application.Resources>
<Application.MainWindow>
    <NavigationWindow Source="MainWindow.xaml" Visibility="Visible"></NavigationWindow>
</Application.MainWindow>

NotifyIconResources.xaml文件：

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                xmlns:local="clr-namespace:FileSharingOnLAN"
                xmlns:tb="http://www.hardcodet.net/taskbar">

<tb:TaskbarIcon x:Key="NotifyIcon"
                IconSource="/Red.ico"
                ToolTipText="Click for popup, right-click for menu"
                ContextMenu="{StaticResource SysTrayMenu}">
    <tb:TaskbarIcon.TrayPopup>
        <Border
            Background="Black"
            Width="200"
            Height="100">
            <StackPanel>
                <Button
                Content="{Binding ButtonContent}"
                VerticalAlignment="Top"
                Command="{Binding ShowImpostazioniWindowCommand}"/>
                <Border
                    Background="Blue"
                    Width="100"
                    Height="50"
                    VerticalAlignment="Bottom"
                    HorizontalAlignment="Left">
                    <StackPanel>
                        <Label                
                            Content="Stato" />
                        <!--<Button
                            Content="{Binding Path="status", Source="{x:Static Application.Current}"}"
                            Command="{Binding StatusClickedCommand}"/>-->
                        <TextBlock Name="label_stato" Text="{Binding Source={x:Static Application.Current}, Path=Properties[status]}"/>
                    </StackPanel>
                </Border>
            </StackPanel>
        </Border>
    </tb:TaskbarIcon.TrayPopup>

    <tb:TaskbarIcon.DataContext>
        <local:NotifyIconViewModel />
    </tb:TaskbarIcon.DataContext>
</tb:TaskbarIcon>

我试图通过使用OnpropertyChanged来修复它，例如：Binding to change the property，但是它不起作用。

在同一项目中，我使用了其他有效的绑定技术，并且我知道如何以编程方式解决此问题，但是我想了解我的错误在哪里，我完全陷入其中。

Answer 1

您需要更改的几件事：

第一个是其自身的状态属性，将其公开：

public string Status
{
    get
    {
        return (string)this.Properties["status"];
    }
    set
    {
        this.Properties["status"] = value;
        NotifyPropertyChanged("Status");
    }
}

protected override void OnStartup(StartupEventArgs e)
{
    base.OnStartup(e);
    Status = "Online";
    ...
}

并将绑定更改为：

<TextBlock Text="{Binding Source={x:Static Application.Current}, Path=Status}" />

工作示例：

<Window x:Class="WpfApplicationTest.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApplicationTest"
        mc:Ignorable="d"
        x:Name="win"
        Title="MainWindow" Height="300" Width="300">
    <Window.Resources>
    </Window.Resources>
    <StackPanel FocusManager.FocusedElement="{Binding ElementName=btnDefault}">
        <TextBox Text="{Binding Source={x:Static Application.Current}, Path=Status}" />
        <TextBlock Text="{Binding Source={x:Static Application.Current}, Path=Status}" />
        <Button>Button 7</Button>
    </StackPanel>
</Window>

Answer 2

找到了可行的解决方案。

我正在像这样更改另一个cs模块中的属性值：

Application.Current.Properties["status"] = "Offline";

此行不能导致该属性的修改，因此我没有对其进行修改。因此，感谢https://stackoverflow.com/a/1609155/10173298，我用以下行代替了它：

((App)Application.Current).setOffline();

setOffline（）是我添加到App.xaml.cs中的一种方法：

public void setOffline()
{
    this.Status = "Offline";
}

WPF绑定仅工作一次

2 个答案: