如何使用 mvvm 禁用文本块?

问题描述

如何使用 mvvm 禁用文本块?

How to disable textblock with mvvm?

我是这个架构的新手，我尝试过 IsEnabled="{Binding IsEnable}"，即:

I'm new with this architecture I tried with IsEnabled="{Binding IsEnable}", i.e:

XAML:

<TextBlock x:Name="version_textBlock" IsEnabled="{Binding IsEnable}" 
          Height="20" Margin="155,144,155,0" TextWrapping="Wrap"
          HorizontalAlignment="Center" Text="mylabel"  
          FontFamily="Moire ExtraBold"
          RenderTransformOrigin="0.582,0.605" Width="210" />

ViewModel.cs:

public bool IsEnable { get; set; }
//constarctor
public ViewModel()
{
  IsEnable = false;
}

但这无济于事

推荐答案

你需要在你的代码后面设置datacontext:

You need to set the datacontext in your code behind:

public partial class MainWindow : Window
{
    public MainWindow ()
    { 
        InitializeComponent();
        this.DataContext = new ViewModel();
    }
}

或者，在您的 XAML 中创建您的视图模型:

Or, alternatively, create your viewmodel in your XAML:

<Window  x:Class="MainWindow"
    ...omitted some lines...
    xmlns:ViewModel="clr-namespace:YourModel.YourNamespace">

    <Window.DataContext>
         <ViewModel:ViewModel />
     </Window.DataContext>

     <your page/>
</Window>

除此之外:我认为您希望您的页面对 ViewModel 中的更改做出反应.因此，您需要在视图模型中实现 INotifyPropertyChanged，如下所示:

Besides that: I think you want your page to react to the changes in the ViewModel. Therefor you need to implement INotifyPropertyChanged in your viewmodel, like this:

public class ViewModel: INotifyPropertyChanged
{
    private string _isEnabled;
    public string IsEnabled
    {
        get { return _isEnabled; }
        set
        {
            if (value == _isEnabled) return;
            _isEnabled= value;
            OnPropertyChanged();
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    [NotifyPropertyChangedInvocator]
    protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
 }

如果模型的值发生变化，INotifyPropertyChange 会更新"您的 UI.

The INotifyPropertyChange "updates" your UI if the value of your model changes.

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