制作AvalonEdit MVVM兼容 [英] Making AvalonEdit MVVM compatible

问题描述

我试图在我的WPF应用程序的Avalon MVVM兼容。从google搜索，我发现 AvalonEdit不MVVM友好，我需要通过出口AvalonEdit状态实现从文本编辑，然后添加必要的依赖属性的派生类。我怕我很迷失在格伦沃尔德先生的回答这里：

I'm trying to make Avalon MVVM compatible in my WPF application. From googling, I found out that AvalonEdit is not MVVM friendly and I need to export the state of AvalonEdit by making a class derived from TextEditor then adding the necessary dependency properties. I'm afraid that I'm quite lost in Herr Grunwald's answer here:

如果你确实需要使用MVVM导出的编辑器的状态，那么我建议你创建一个类的文本编辑派生它增加了必要的依赖属性，并将其与AvalonEdit实际性能同步。

If you really need to export the state of the editor using MVVM, then I suggest you create a class deriving from TextEditor which adds the necessary dependency properties and synchronizes them with the actual properties in AvalonEdit.

有没有人有一个例子，或对如何实现这一好建议？

Does anyone have an example or have good suggestions on how to achieve this?

推荐答案

杜林格伦沃尔德在谈论用的文本编辑特性=HTTP：// MSDN .microsoft.com / EN-US /库/ ms752914.aspx>依赖属性的，这样就可以绑定到他们。其基本思路是这样的（使用的 CaretOffset 的属性为例）：

Herr Grunwald is talking about wrapping the TextEditor properties with dependency properties, so that you can bind to them. The basic idea is like this (using the CaretOffset property for example):

public class MvvmTextEditor : TextEditor, INotifyPropertyChanged
{
    public static DependencyProperty CaretOffsetProperty = 
        DependencyProperty.Register("CaretOffset", typeof(int), typeof(MvvmTextEditor),
        // binding changed callback: set value of underlying property
        new PropertyMetadata((obj, args) =>
        {
            MvvmTextEditor target = (MvvmTextEditor)obj;
            target.CaretOffset = (int)args.NewValue;
        })
    );

    public new string Text
    {
        get { return base.Text; }
        set { base.Text = value; }
    }

    public new int CaretOffset
    {
        get { return base.CaretOffset; }
        set { base.CaretOffset = value; }
    }

    public int Length { get { return base.Text.Length; } }

    protected override void OnTextChanged(EventArgs e)
    {
        RaisePropertyChanged("Length");
        base.OnTextChanged(e);
    }

    public event PropertyChangedEventHandler PropertyChanged;
    public void RaisePropertyChanged(string info)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(info));
        }
    }
}

现在的 CaretOffset 已被包裹在一个DependencyProperty的，可以将其绑定到一个属性，比如偏移在您的视图模型。为了举例说明，一个滑块控件的值绑定到同一个视图模型属性偏移，并查看当您移动滑块，阿瓦隆编辑器的光标位置被更新：

Now that the CaretOffset has been wrapped in a DependencyProperty, you can bind it to a property, say Offset in your View Model. For illustration, bind a Slider control's value to the same View Model property Offset, and see that when you move the Slider, the Avalon editor's cursor position gets updated:

<Window x:Class="AvalonDemo.TestWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:avalonEdit="http://icsharpcode.net/sharpdevelop/avalonedit"
    xmlns:avalonExt="clr-namespace:WpfTest.AvalonExt"
    DataContext="{Binding RelativeSource={RelativeSource Self},Path=ViewModel}">
  <StackPanel>
    <avalonExt:MvvmTextEditor Text="Hello World" CaretOffset="{Binding Offset}" x:Name="editor" />
    <Slider Minimum="0" Maximum="{Binding ElementName=editor,Path=Length,Mode=OneWay}" 
        Value="{Binding Offset}" />
    <TextBlock Text="{Binding Path=Offset,StringFormat='Caret Position is {0}'}" />
    <TextBlock Text="{Binding Path=Length,ElementName=editor,StringFormat='Length is {0}'}" />
  </StackPanel>
</Window>

测试code-背后

namespace AvalonDemo
{
    public partial class TestWindow : Window
    {
        public AvalonTestModel ViewModel { get; set; }

        public TestWindow()
        {
            ViewModel = new AvalonTestModel();
            InitializeComponent();
        }
    }
}

测试视图模型

public class AvalonTestModel : INotifyPropertyChanged
{
    private int _offset;

    public int Offset 
    { 
        get { return _offset; } 
        set 
        { 
            _offset = value; 
            RaisePropertyChanged("Offset"); 
        } 
    }

    public event PropertyChangedEventHandler PropertyChanged;
    public void RaisePropertyChanged(string info)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(info));
        }
    }
}

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