我创建了一个继承自AvalonEdit的自定义TextEditor控件.我这样做是为了方便使用这个编辑器控件来使用MVVM和Caliburn Micro. [为了显示目的而减少] MvvTextEditor类是
public class MvvmTextEditor : TextEditor, INotifyPropertyChanged
{
public MvvmTextEditor()
{
TextArea.SelectionChanged += TextArea_SelectionChanged;
}
void TextArea_SelectionChanged(object sender, EventArgs e)
{
this.SelectionStart = SelectionStart;
this.SelectionLength = SelectionLength;
}
public static readonly DependencyProperty SelectionLengthProperty =
DependencyProperty.Register("SelectionLength", typeof(int), typeof(MvvmTextEditor),
new PropertyMetadata((obj, args) =>
{
MvvmTextEditor target = (MvvmTextEditor)obj;
target.SelectionLength = (int)args.NewValue;
}));
public new int SelectionLength
{
get { return base.SelectionLength; }
set { SetValue(SelectionLengthProperty, value); }
}
public event PropertyChangedEventHandler PropertyChanged;
public void RaisePropertyChanged([CallerMemberName] string caller = null)
{
var handler = PropertyChanged;
if (handler != null)
PropertyChanged(this, new PropertyChangedEventArgs(caller));
}
}
现在,在持有此控件的视图中,我有以下XAML:
<Controls:MvvmTextEditor
Caliburn:Message.Attach="[Event TextChanged] = [Action DocumentChanged()]"
TextLocation="{Binding TextLocation, Mode=TwoWay}"
SyntaxHighlighting="{Binding HighlightingDefinition}"
SelectionLength="{Binding SelectionLength,
Mode=TwoWay,
NotifyOnSourceUpdated=True,
NotifyOnTargetUpdated=True}"
Document="{Binding Document, Mode=TwoWay}"/>
我的问题是SelectionLength(和SelectionStart,但我们只考虑现在的长度,因为问题是相同的).如果我用鼠标选择了某些东西,从View到View模型的绑定效果很好.现在,我编写了一个find和replace实用程序,我想从后面的代码中设置SelectionLength(在TextEditor控件中可以获取和设置).在我的View Model中,我只是设置SelectionLength = 50,我在View Model中实现了这个
private int selectionLength;
public int SelectionLength
{
get { return selectionLength; }
set
{
if (selectionLength == value)
return;
selectionLength = value;
Console.WriteLine(String.Format("Selection Length = {0}", selectionLength));
NotifyOfPropertyChange(() => SelectionLength);
}
}
当我设置SelectionLength = 50时,DependencyProperty SelectionLengthProperty不会在MvvmTextEditor类中更新,就像对我的控件的TwoWay绑定失败但使用Snoop没有任何迹象.我认为这只会通过绑定工作,但似乎并非如此.
有什么简单的我缺少,或者我必须在MvvmTextEditor类中设置和事件处理程序,它监听我的视图模型中的更改并更新DP本身[这表明它自己的问题]?
谢谢你的时间.
最佳答案 这是因为DependencyProperty中的Getter和Setter只是一个.NET Wrapper.框架将使用GetValue和SetValue本身.
您可以尝试从DependencyProperty访问PropertyChangedCallback并设置正确的值.
public int SelectionLength
{
get { return (int)GetValue(SelectionLengthProperty); }
set { SetValue(SelectionLengthProperty, value); }
}
// Using a DependencyProperty as the backing store for SelectionLength. This enables animation, styling, binding, etc...
public static readonly DependencyProperty SelectionLengthProperty =
DependencyProperty.Register("SelectionLength", typeof(int), typeof(MvvmTextEditor), new PropertyMetadata(0,SelectionLengthPropertyChanged));
private static void SelectionLengthPropertyChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e)
{
var textEditor = obj as MvvmTextEditor;
textEditor.SelectionLength = e.NewValue;
}