文本框MVVM数据绑定

问题描述：

我正在编写WPF计算器应用程序。在此应用程序中，我具有TextBox来根据OnWindowKeyDown事件获取和设置输入（输入插入/验证并作为用户类型返回到TextBox）。

I'm writing a WPF calculator app. In this application I have TextBox that get and set the input according to the OnWindowKeyDown event (input insert/validated and returned to the TextBox as the user type).

如果用户键入：

3-> validate == true--> print to TextBox '3'
y-> validate == false -> ignore
3-> validate == true --> print to TeextBox "33"

我想按字符获取输入字符（我有一个状态模式类，它对添加的每个char做出反应），但是我需要将结果作为字符串返回。

I want to get the input char by char (I have a State Pattern class that react to each char added), but I need to return the result as a string.

如何使用MVVM将数据与textBox相互传输？设计？

How can I transfer my data from and to the textBox, with the MVVM design?

答

应该足以绑定文本将 TextBox 的code>属性更改为 ViewModel 的属性。

It should be enough to bind a Text property of TextBox to ViewModel's property.

例如：

//ViewModel 
public class MyViewModel : INotifyPropertyChanged
{
     private string textBoxText = string.Empty;
     public string TextBoxText 
     {
        get {return textBoxText;}
        set {
           textBoxText = value;
           OnPropertyChanged("TextBoxText "..);
        }
     }
}

绑定 MyViewModel 到 Form ， TextBox DataContext / code>或其他...简而言之，使其以某种方式可用于您的 TextBox 。

Bind MyViewModel to a DataContext of your Form, TextBox or whatever... in short make it available to your TextBoxin some way.

定义一个转换器，每次调用该方法的时间 TextBox 集的> Text 属性。

Define a Converter whom methods will be invoked every time Text property of TextBox set.

public class TextContenyConverter: IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {

        // validate input and return appropriate value
    }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotSupportedException();
    }
}

绑定到 XAML 考虑到 DataContext 是类型 MyViewModel

其中， TextContenyConverterObject 是类型为 TextContenyConverter 的对象>定义为静态资源。

where TextContenyConverterObject is an object of type TextContenyConverter defined like a static resource.

这只是一个例子。

这是对 ValueConverters 。

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