具有命令绑定的键绑定不适用于TextBox UpdateSourceTrigger LostFocus [英] KeyBinding with Command Binding dont work with TextBox UpdateSourceTrigger LostFocus

问题描述

我正在使用MVVM，并且存在以下问题.我的TextBox.Text与UpdateSourceTrigger = LostFocus绑定(这就是用户想要的).我有一个带有SaveCommand CommandBinding的按钮-这可行.现在我有一个Strng + S的KeyBinding，也执行SaveCommand.这就是问题所在:当我在文本框"中按Strg + s时，所做的更改不在视图模型中.

I'm using MVVM and have the following problem. My TextBox.Text is bound with UpdateSourceTrigger=LostFocus (thats what the user want). I have a Button with a SaveCommand CommandBinding - this works. Now i have a KeyBinding with Strg+S wich also execute the SaveCommand. And here is the problem: when i m in the Textbox and press Strg+s, the changes are not in the viewmodel.

是否可以通过KeyBinding和TextBox UpdateSourceTrigger = LostFocus一起获得MVVM命令?

is there any way to get MVVM Commands with KeyBinding and TextBox UpdateSourceTrigger=LostFocus working together?

一些代码来检查问题

<Window>
<Window.InputBindings>
    <KeyBinding Key="S" Modifiers="Control" Command="{Binding SaveCommand}"></KeyBinding>
</Window.InputBindings>
<Grid>
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="Auto"/>
    </Grid.RowDefinitions>      
    <TextBox Grid.Row="0" Text="{Binding MyText1, UpdateSourceTrigger=LostFocus}" Width="100"></TextBox>
    <Button Grid.Row="1" Content="_Save" Command="{Binding SaveCommand}" IsDefault="True"></Button> 
</Grid>
</Window>

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

public class Viewmodel : INPCBase
{
    private string _myText1;
    private Lazy<DelegateCommand> _save;

    public Viewmodel()
    {
        this._save = new Lazy<DelegateCommand>(()=> new DelegateCommand(this.SaveCommandExecute));
    }

    private void SaveCommandExecute()
    {
        MessageBox.Show(MyText1);
    }

    public string MyText1
    {
        get { return _myText1; }
        set { _myText1 = value; this.NotifyPropertyChanged(()=>MyText1);}
    }

    public ICommand SaveCommand
    {
        get { return _save.Value; }
    }
}

推荐答案

目前，我想到了以下解决方法.在我定义我的KeyBindings的usercontrol/views中，例如，我还监听PreviewKeyDown事件并将焦点设置到下一个元素.按下Strg + S.

at the moment i came up with the following workaround. within the usercontrol/views where i define my KeyBindings, i also listen to the PreviewKeyDown event and set the focus to the next element when eg. Strg+S is pressed.

    private void Window_PreviewKeyDown(object sender, KeyEventArgs e)
    {
        if (e.Key == Key.S && e.KeyboardDevice.Modifiers == ModifierKeys.Control)
        {
            var fe = Keyboard.FocusedElement as UIElement;

            if (fe != null)
            {
               fe.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
            }

        }
    }

这篇关于具有命令绑定的键绑定不适用于TextBox UpdateSourceTrigger LostFocus的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！