C# WPF：未能清除列表中的项目（&F）；添加新频道

我正在WPF中开发一个应用程序，我应该在其中动态生成UI组件并对其执行一些操作。我的做法如下：

XAML:

<Grid Visibility="{Binding IsAvailable, Converter={StaticResource booltovisibility}}">            
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="170" />
        <ColumnDefinition />
        <ColumnDefinition Width="130" />
        <ColumnDefinition Width="115" />
    </Grid.ColumnDefinitions>

    <Label Grid.Column="0" Content="{Binding ChannelName}" />
    <TextBox Grid.Column="1" Text="{Binding VoltageText}" />
    <Button Grid.Column="1" Content="Set" CommandParameter="{Binding VoltageText}" Command="{Binding VoltageCommand}" />
    <Label Grid.Column="2" Content="{Binding CurrentText}"  />
    <ToggleButton Grid.Column="3" Content="On" />
</Grid>

<Button Content="Bavaria" Name="BavariaBtn" Click="BavariaBtn_Click" />

public void OnChildAdd()
    {            
        foreach (VoltageBoardChannel mVoltageChannelViewModel in mVoltageViewModel.VoltageChannelList)
        {
            VoltageChannelView mVoltageChannelView = new VoltageChannelView();
            mVoltageChannelView.Margin = new Thickness(2);
            mVoltageChannelView.ChannelInfo = mVoltageChannelViewModel;
            //Some Code to add the item
        }
    }

    private void BavariaBtn_Click(object sender, RoutedEventArgs e)
    {
        VoltageViewModel mVoltageViewModel = new VoltageViewModel();

        // Here List should get cleared and Bavaria 2 items should be added
        mVoltageViewModel.VoltageChannelList.Clear();
        mVoltageViewModel.VoltageChannelList = mVoltageViewModel.bavaria2Channels;            
        OnChildAdd();
    }      

public List<VoltageBoardChannel> channelList = null;        

    public List<VoltageBoardChannel> bavaria2Channels = new List<VoltageBoardChannel>
    {
         new VoltageBoardChannel { ChannelName = "VDD__MAIN", IsAvailable = true},
         new VoltageBoardChannel { ChannelName = "VDD__IO__AUD", IsAvailable = true},
         new VoltageBoardChannel { ChannelName = "VDD__CODEC__AUD", IsAvailable = true},
         new VoltageBoardChannel { ChannelName = "VDD__DAL__AUD", IsAvailable = true},
         new VoltageBoardChannel { ChannelName = "VDD__DPD__AUD", IsAvailable = true},
         new VoltageBoardChannel { ChannelName = "VDD__PLL__AUD", IsAvailable = true},
         new VoltageBoardChannel { ChannelName = "VDD__AMP1__AUD", IsAvailable = true},
    };

    private ICommand m_voltageCommand;        

    public List<VoltageBoardChannel> bavaria1Channels = new List<VoltageBoardChannel>
    {
         new VoltageBoardChannel { ChannelName = "VDD__MAIN", IsAvailable = true},
         new VoltageBoardChannel { ChannelName = "VDD__IO", IsAvailable = true},
         new VoltageBoardChannel { ChannelName = "VDD__CODEC", IsAvailable = true},
         new VoltageBoardChannel { ChannelName = "VDD__LDO", IsAvailable = true},
         new VoltageBoardChannel { ChannelName = "VDD__AMP", IsAvailable = true},  
    };            

    public VoltageViewModel()
    {
        channelList = new List<VoltageBoardChannel>(0);
        channelList = bavaria1Channels;            
        m_voltageCommand = new DelegateVoltageCommand(x => SetCommandExecute(x));            
    }

    public List<VoltageBoardChannel> VoltageChannelList
    {
        get 
        { 
            return channelList; 
        }

        set
        { 
            channelList = value;
            OnPropertyChanged("ChannelList");
        }
    }

private string mChannelName;
    public string ChannelName
    {
        get
        {
            return mChannelName;
        }
        set
        {
            mChannelName = value;
            OnPropertyChanged("ChannelName");
        }
    }

    private bool mIsAvailable;
    public bool IsAvailable
    {
        get
        {
            return mIsAvailable;
        }
        set
        {
            mIsAvailable = value;
            OnPropertyChanged("IsAvailable");
        }
    }        

    public ICommand VoltageCommand { get; set; }

视图模型：

<Grid Visibility="{Binding IsAvailable, Converter={StaticResource booltovisibility}}">            
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="170" />
        <ColumnDefinition />
        <ColumnDefinition Width="130" />
        <ColumnDefinition Width="115" />
    </Grid.ColumnDefinitions>

    <Label Grid.Column="0" Content="{Binding ChannelName}" />
    <TextBox Grid.Column="1" Text="{Binding VoltageText}" />
    <Button Grid.Column="1" Content="Set" CommandParameter="{Binding VoltageText}" Command="{Binding VoltageCommand}" />
    <Label Grid.Column="2" Content="{Binding CurrentText}"  />
    <ToggleButton Grid.Column="3" Content="On" />
</Grid>

<Button Content="Bavaria" Name="BavariaBtn" Click="BavariaBtn_Click" />

public void OnChildAdd()
    {            
        foreach (VoltageBoardChannel mVoltageChannelViewModel in mVoltageViewModel.VoltageChannelList)
        {
            VoltageChannelView mVoltageChannelView = new VoltageChannelView();
            mVoltageChannelView.Margin = new Thickness(2);
            mVoltageChannelView.ChannelInfo = mVoltageChannelViewModel;
            //Some Code to add the item
        }
    }

    private void BavariaBtn_Click(object sender, RoutedEventArgs e)
    {
        VoltageViewModel mVoltageViewModel = new VoltageViewModel();

        // Here List should get cleared and Bavaria 2 items should be added
        mVoltageViewModel.VoltageChannelList.Clear();
        mVoltageViewModel.VoltageChannelList = mVoltageViewModel.bavaria2Channels;            
        OnChildAdd();
    }      

public List<VoltageBoardChannel> channelList = null;        

    public List<VoltageBoardChannel> bavaria2Channels = new List<VoltageBoardChannel>
    {
         new VoltageBoardChannel { ChannelName = "VDD__MAIN", IsAvailable = true},
         new VoltageBoardChannel { ChannelName = "VDD__IO__AUD", IsAvailable = true},
         new VoltageBoardChannel { ChannelName = "VDD__CODEC__AUD", IsAvailable = true},
         new VoltageBoardChannel { ChannelName = "VDD__DAL__AUD", IsAvailable = true},
         new VoltageBoardChannel { ChannelName = "VDD__DPD__AUD", IsAvailable = true},
         new VoltageBoardChannel { ChannelName = "VDD__PLL__AUD", IsAvailable = true},
         new VoltageBoardChannel { ChannelName = "VDD__AMP1__AUD", IsAvailable = true},
    };

    private ICommand m_voltageCommand;        

    public List<VoltageBoardChannel> bavaria1Channels = new List<VoltageBoardChannel>
    {
         new VoltageBoardChannel { ChannelName = "VDD__MAIN", IsAvailable = true},
         new VoltageBoardChannel { ChannelName = "VDD__IO", IsAvailable = true},
         new VoltageBoardChannel { ChannelName = "VDD__CODEC", IsAvailable = true},
         new VoltageBoardChannel { ChannelName = "VDD__LDO", IsAvailable = true},
         new VoltageBoardChannel { ChannelName = "VDD__AMP", IsAvailable = true},  
    };            

    public VoltageViewModel()
    {
        channelList = new List<VoltageBoardChannel>(0);
        channelList = bavaria1Channels;            
        m_voltageCommand = new DelegateVoltageCommand(x => SetCommandExecute(x));            
    }

    public List<VoltageBoardChannel> VoltageChannelList
    {
        get 
        { 
            return channelList; 
        }

        set
        { 
            channelList = value;
            OnPropertyChanged("ChannelList");
        }
    }

private string mChannelName;
    public string ChannelName
    {
        get
        {
            return mChannelName;
        }
        set
        {
            mChannelName = value;
            OnPropertyChanged("ChannelName");
        }
    }

    private bool mIsAvailable;
    public bool IsAvailable
    {
        get
        {
            return mIsAvailable;
        }
        set
        {
            mIsAvailable = value;
            OnPropertyChanged("IsAvailable");
        }
    }        

    public ICommand VoltageCommand { get; set; }

您可以注意到，在ViewModel类中，Bavaria 1在启动时显示。这里我主要想清除这些项目，然后在

BavariaBtn_Click（）

上显示Bavaria 2项目，如xaml.cs类所示。我正在尝试这样做，但是列表没有被清除，尽管项目正在被添加

---

我怎样才能实现它？：）

简单列表不发送有关其元素更改的通知。它不实现

INotifyCollectionChanged

接口

observeablecollection

使用

ObservableCollection

而不是您的VoltageChannelList属性的列表，然后

---

不需要更改属性（“VoltageChannelList”）在setter中，您正在清除一个局部变量。XAML不知道您已经这样做了，事实上除了方法本身之外，没有人知道您已经清除了局部变量：

// Nobody knows the trouble I've seen...
VoltageViewModel mVoltageViewModel = new VoltageViewModel();

// Here List should get cleared and Bavaria 2 items should be added
mVoltageViewModel.VoltageChannelList.Clear();

MVVM清除列表的方法是向视图模型添加一个Clear命令：

public ICommand ClearCommand { get; private set; }

// ...

public VoltageViewModel(...)
{
    // ...
    this.ClearCommand = new DelegateCommand(
        () => this.VoltageChannelList.Clear(),
        () => this.VoltageChannelList.Count > 0);
}

然后在XAML中：

<Button Content="Bavaria" x:Name="BavariaBtn" Command="{Binding ClearCommand}" />

---

首先。。。您确实需要使用ObservableCollection。该列表不会像@Miklos所说的那样发送通知

第二，当你这样做时：

mVoltageViewModel.VoltageChannelList = mVoltageViewModel.bavaria2Channels;

您正在删除VoltageChannelList列表。你不能这样做。您必须在列表上迭代并手动复制项目

private void BavariaBtn_Click(object sender, RoutedEventArgs e)   
    {   
        VoltageViewModel mVoltageViewModel = new VoltageViewModel();   

        // Here List should get cleared and Bavaria 2 items should be added   
        mVoltageViewModel.VoltageChannelList.Clear();   

        foreach (VoltageBoardChannel channel in  mVoltageViewModel.bavaria2Channels) 
            mVoltageViewModel.VoltageChannelList.Add(channel);
    }  

---

谢谢你的回复。我用

ObservableCollection

试过了，但还是没有在点击按钮时清除列表。谢谢你的回复。我试过了，但仍然没有清除项目或添加新项目。注意：我的.cs文件中已经有了

BavariaBtn\u Click（）

，现在如果我使用

命令

，你不认为这会导致歧义吗？？？我试过了，点击按钮，似乎什么也没发生。既然您推荐clearcommand，我们如何既清除列表又添加新频道？