单击按钮时无法检索文本框值

Question

看标题，它可能看起来很简单，但它有点棘手。我正在开发一个 wpf 应用程序，我需要在其中动态生成按钮、标签和文本框。在我的 VoltageView XAml 文件中，我创建了一个堆栈面板。在我的 VoltageChannelView xaml 文件中，我创建了所有 UI 组件。

我在一定程度上实现了如下：

电压视图：

<Grid Grid.Row="1" Style="{DynamicResource styleBackground}" Name="VoltageChannels" >
        <StackPanel Height="Auto" Name="stackPanel" Width="Auto" MinHeight="300"></StackPanel>
</Grid>

VoltageChannelView：

<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}" />

我将上述动态生成的 Ui 组件添加到我的 VoltageView.xaml.cs 中的堆栈面板中，如下所示：

VoltageViewModel mVoltageViewModel = new VoltageViewModel();

// Called in constructor
public void OnChildAdd()
    {            
        foreach (VoltageBoardChannel mVoltageChannelViewModel in mVoltageViewModel.VoltageChannelList)
        {
            VoltageChannelView mVoltageChannelView = new VoltageChannelView();
            mVoltageChannelView.Margin = new Thickness(2);
            mVoltageChannelView.ChannelInfo = mVoltageChannelViewModel;
            stackPanel.Children.Add(mVoltageChannelView);
        }
    }

VoltageViewModel 类：

public ObservableCollection<VoltageBoardChannel> channelList = null;

    public ObservableCollection<VoltageBoardChannel> redhookChannels = new ObservableCollection<VoltageBoardChannel>
    {             
         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}             
    };       

    public ObservableCollection<VoltageBoardChannel> bavaria1Channels = new ObservableCollection<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 ObservableCollection<VoltageBoardChannel>();
        channelList = bavaria1Channels;          

    }

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

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

    RelayCommand _voltageCommand;
    public ICommand VoltageCommand
    {
        get
        {
            if (_voltageCommand == null)
            {
                _voltageCommand = new RelayCommand(param => this.DoSomethingExecute, param => this.DoSomethingCanExecute);
            }
            return _voltageCommand;
        }
    }

    public bool DoSomethingCanExecute(object param)
    {
        return true;
    }

    public void DoSomethingExecute(object param)
    {

    }

正如您在启动时看到的那样，显示 BAVARIA1 频道。

VoltageBoardChannel（模型）类：

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

    private bool mIsAvailable;
    public bool IsAvailable
    {
        get; set;
    }

    string voltageText = string.Empty;
    public string VoltageText
    {
        get
        {
            return voltageText;
        }

        set
        {
            voltageText = value;
            OnPropertyChanged("VoltageText");
        }
    }      

因此，当我运行该应用程序时，它会动态显示 bavaria1 频道 4 次，如列表中维护的那样。现在在每个动态生成的控件上都有一个文本框和按钮。

您可以在VoltageChannelView.xaml 中注意到我已经完成了绑定 bw 按钮和文本框。我想在文本框中输入值并单击 SET 按钮，它应该检索输入的值，以便可以完成进一步的操作。基本上应该有一个 SET 按钮的事件，它应该将 Textbox 中写入的文本作为参数传递。

我怎样才能实现它？ :)

Answer 1

当我看到这一点时，您是否错过了您的命令的实施。 您需要的是处理您的命令的逻辑。

复制本文来源WPF Apps With The Model-View-ViewModel Design Pattern

RelayCommand 类

public class RelayCommand : ICommand
{
    #region Fields

    readonly Action<object> _execute;
    readonly Predicate<object> _canExecute;        

    #endregion // Fields

    #region Constructors

    public RelayCommand(Action<object> execute)
    : this(execute, null)
    {
    }

    public RelayCommand(Action<object> execute, Predicate<object> canExecute)
    {
        if (execute == null)
            throw new ArgumentNullException("execute");

        _execute = execute;
        _canExecute = canExecute;           
    }
    #endregion // Constructors

    #region ICommand Members

    [DebuggerStepThrough]
    public bool CanExecute(object parameter)
    {
        return _canExecute == null ? true : _canExecute(parameter);
    }

    public event EventHandler CanExecuteChanged
    {
        add { CommandManager.RequerySuggested += value; }
        remove { CommandManager.RequerySuggested -= value; }
    }

    public void Execute(object parameter)
    {
        _execute(parameter);
    }

    #endregion // ICommand Members
}

您的命令实现应该如下所示：

RelayCommand _voltageCommand ;
public ICommand VoltageCommand 
{
    get
    {
        if (_voltageCommand == null)
        {
            _voltageCommand = new RelayCommand(this.DoSomethingExecute,
                this.DoSomethingCanExecute);
        }
        return _voltageCommand;
    }
}

执行方法：

public void DoSomethingExecute(object param)
{
    // param is your string        
    //Do Something with VoltageText
}

CanExecute方法

public bool DoSomethingCanExecute(object param)
{
    return true;        
}