Question

当我尝试使用双向数据绑定更改边框的背景颜色时，我收到以下异常。

{"Must create DependencySource on same Thread as the DependencyObject."}

当我第一次遇到这个错误时，我改变了我的代码，将颜色作为静态资源，希望它可以解决问题，但它没有用。

XAML

<Grid x:Name="BgGrid">
    <Grid.Resources>
        <Color x:Key="ACGreen">#FF0A7E07</Color>
        <Color x:Key="ACYellow">#FFE2BD00</Color>
        <Color x:Key="ACRed">#FFAF0B01</Color>
        <SolidColorBrush x:Key="GreenBrush" Color="{StaticResource ACGreen}" />
        <SolidColorBrush x:Key="YellowBrush" Color="{StaticResource ACYellow}" />
        <SolidColorBrush x:Key="RedBrush" Color="{StaticResource ACRed}" />
    </Grid.Resources>
    <TabControl Style="{StaticResource LeftTabControl}" Background="#FAFAFAFA" HorizontalAlignment="Stretch">
        <TabItem x:Name="ConnectionLabelTab" Style="{StaticResource Tab2}" Focusable="False">
            <TabItem.HeaderTemplate>
                <DataTemplate>
                    <Border x:Name="ConnectionLabelBorder" Background="{Binding LabelColor, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" Width="70"
                        DataContext="{Binding RelativeSource={RelativeSource AncestorType=UserControl}, Path=DataContext}">
                        <TextBlock x:Name="ConnectionLabelText"
                            Text="{Binding LabelText, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" Padding="0,4,0,4"
                            Foreground="#FAFAFAFA" HorizontalAlignment="Center" VerticalAlignment="Center" 
                            FontSize="10"/>
                    </Border>
                </DataTemplate>
            </TabItem.HeaderTemplate>
        </TabItem>
    </TabControl>
</Grid>

xaml.cs

public partial class TabPanel : UserControl, INotifyPropertyChanged
{
    Brush labelcolor;
    String labeltext;

    public TabPanel()
    {
        InitializeComponent();

        labelcolor = BgGrid.Resources["RedBrush"] as Brush;
        labeltext = "Disconnected";
    }

    public Brush LabelColor 
    { 
        get { return labelcolor; }
        set
        {
            labelcolor = value;
            PropertyChanged(this, new PropertyChangedEventArgs("LabelColor"));
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    public void SetConnected()
    {
        LabelColor = BgGrid.Resources["GreenBrush"] as Brush;
        LabelText = "Connected";
    }
}

是否有更好/正确的方法来动态更改背景颜色？如何修复我的代码以停止获取此System.ArguementException？如果我注释掉设置LabelColor，代码工作正常，文本按预期更改。

Answer 1

我会不确定这是否有效，但您可能需要在调度员上调用。

public void SetConnected()
{
    Dispatcher.BeginInvoke(new Action(() => {
      LabelColor = BgGrid.Resources["GreenBrush"] as Brush;
      LabelText = "Connected";
   });
}

原因是，如果从UI线程的某个地方调用SetConnected方法（如计时器或未直接从UI调用的东西），则需要“重新集成”回UI线程以便更新任何UI属性。这在处理WPF绑定时很常见。

尝试使用双向绑定设置背景时，WPF会抛出System.ArgumentException

1 个答案: