Question

我在这里有一些学术问题。看看标记：

<Grid  Margin="10,10,10,10">
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto" />
        <RowDefinition Height="Auto" />
    </Grid.RowDefinitions>
    <ComboBox SelectedIndex="{Binding SelectedIndex}"
                Margin="5"
                Width="100">
        <i:Interaction.Triggers>
            <i:EventTrigger EventName="SelectionChanged">
                <i:InvokeCommandAction Command="{Binding TestCommand}" 
                                        CommandParameter="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ComboBox}, 
                                        Path=SelectedIndex}"/>
            </i:EventTrigger>
        </i:Interaction.Triggers>
        <ComboBoxItem>Item1</ComboBoxItem>
        <ComboBoxItem>Item2</ComboBoxItem>
        <ComboBoxItem>Item3</ComboBoxItem>
    </ComboBox>
    <Button Grid.Row="1" 
            Content="Set SelectedIndex to 0" 
            Width="100" 
            Command="{Binding ButtonCommand}"
            Margin="5">
    </Button>
</Grid>

这是DataContext类。

class Class1Context : ViewModelBase
{
    private int _selectedIndex;
    public Int32 SelectedIndex
    {
        get { return _selectedIndex; }
        set
        {
            _selectedIndex = value;
            RaisePropertyChanged("SelectedIndex");
        }
    }

    private RelayCommand<Object> _testCommand;
    public RelayCommand<Object> TestCommand
    {
        get
        {
            return _testCommand ?? (_testCommand =
                new RelayCommand<Object>(TestMethod));
        }
    }

    private void TestMethod(Object obj)
    {
        var index = (Int32) obj;
        var selIndex = SelectedIndex;
    }


    private RelayCommand _buttonCommand;
    public RelayCommand ButtonCommand
    {
        get
        {
            return _buttonCommand ?? (_buttonCommand =
                new RelayCommand(ButtonCommandMethod));
        }
    }

    private void ButtonCommandMethod()
    {
        SelectedIndex = 0;
    }
}

那么，问题出在哪里？这里是。当我选择Item2或Item3时，SelectedIndex属性等于1或2.例如，我现在点击Item2和SelectedIndex等于1。因此，当我点击Button并将SelectedIndex设置为0时，它会在SelectionChanged中生成事件Combobox。这是逻辑上的。然后，event触发有界命令TestCommand。在TestMethod索引（CommandParameter）中等于1（ 1！）并且这是一个问题，尽管SelectedIndex DataContext等于为0（零）。那么，它是Wpf错误还是其他什么？

Answer 1

我是这样做的：

rootProject.name = 'modules-business'
include 'business-core'
.. snip business-* modules ..
// includeBuild '../modules-technical/'

这种方式对我来说很好。我知道每个ComboBoxItem使用相同的代码会产生一些代码开销。

如果您的ComboBox需要动态加载，那么您应该能够在代码中添加Interaction.Triggers

Answer 2

            <i:EventTrigger EventName="SelectionChanged">
                <i:InvokeCommandAction Command="{Binding TestCommand}" ></i:InvokeCommandAction>
            </i:EventTrigger>
        </i:Interaction.Triggers>

Wpf Combobox SelectionChanged事件CommandParameter混淆

2 个答案: