TabControl命令绑定

Question

我正在使用从Stackoverflow提取的以下代码。

我想在SelectionChanged事件中将字符串从一种视图模型转移到另一种视图模型。但是，当我单击Tab2时，我得到了Tab2消息框，但是当我单击Tab1时，我得到了两个消息框，它们都在执行。单击Tab1时相同，都将看到两个消息框。

MainView.xaml

<TabControl>
 <TabItem Header="My tab 1" Selector.IsSelected="{Binding IsMyTab1Selected}"> ... </TabItem>
 <TabItem Header="My tab 2" Selector.IsSelected="{Binding IsMyTab2Selected}"> ... </TabItem>
</TabControl>

MainViewModel.cs

public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged(string propertyName) {
 PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}

public MainViewModel() {
 PropertyChanged += handlePropertyChanged;
}

public bool IsMyTab1Selected {
 get { return _IsMyTab1Selected ; }
 set {
  if (value != _IsMyTab1Selected ) {
   _IsMyTab1Selected = value;
   OnPropertyChanged("IsMyTab1Selected ");
  }
 }
}
private bool _IsMyTab1Selected = false;

public bool IsMyTab2Selected {
 get { return _IsMyTab2Selected ; }
 set {
  if (value != _IsMyTab2Selected ) {
   _IsMyTab2Selected = value;
   OnPropertyChanged("IsMyTab2Selected ");
  }
 }
}
private bool _IsMyTab2Selected = false;

private void handlePropertyChanged(object sender, PropertyChangedEventArgs e) {
 if (e.PropertyName == "IsMyTab1Selected") {
   MessageBox.Show("Tab_1 Clicked!");
 } else if (e.PropertyName == "IsMyTab2Selected") {
   MessageBox.Show("Tab_2 Clicked!");
 }
}

我无法获得互斥，请指出我错了。

Answer 1

绑定也将在deselection上更新。您需要在处理程序中检查e.NewValue，或者为什么不直接检查_IsMyTab1Selected等？

Answer 2

选项1

您可以将设置器更改为仅在OnPropertyChanged(..)时才调用value == true（实际上if（value）足够，为清楚起见，我添加了== true）：

public bool IsMyTab1Selected
{
    get { return _IsMyTab1Selected; }
    set
    {
        if (value != _IsMyTab1Selected)
        {
            _IsMyTab1Selected = value;
            if (value == true)
                OnPropertyChanged("IsMyTab1Selected");
        }
    }
}

public bool IsMyTab2Selected
{
    get { return _IsMyTab2Selected; }
    set
    {
        if (value != _IsMyTab2Selected)
        {
            _IsMyTab2Selected = value;
            if(value == true)
                OnPropertyChanged("IsMyTab2Selected");
        }
    }
}

选项2

或者您可以像这样检查值是否为handlePropertyChange()

private void handlePropertyChanged(object sender, PropertyChangedEventArgs e)
{
    if (e.PropertyName == "IsMyTab1Selected")
    {
        if(IsMyTab1Selected)
            MessageBox.Show("Tab_1 Clicked!");
    }
    else if (e.PropertyName == "IsMyTab2Selected")
    {
        if(IsMyTab2Selected)
            MessageBox.Show("Tab_2 Clicked!");
    }
}