在Windows Phone中使用C＃更改StackPanel內部Textblock的前景色

Question

這是我的xaml

 <ListBox   Margin="3,60,1,10" BorderThickness="2" Grid.Row="1" Name="lstAnnouncement" Tap="lstAnnouncement_Tap" Width="476" d:LayoutOverrides="VerticalMargin">
        <ListBox.ItemTemplate>

            <DataTemplate>

                <StackPanel   Name="thispanel"  Grid.Row="1" Orientation="Horizontal" Height="120" Width="478" >

                    <StackPanel.Background>
                        <ImageBrush ImageSource="Images/Text-ALU.png" Stretch="Fill" />
                        <!--<SolidColorBrush  Color="{Binding Path=background}"/>-->
                    </StackPanel.Background>
                    <toolkit:ContextMenuService.ContextMenu>
                        <toolkit:ContextMenu>
                            <toolkit:MenuItem Header="Delete" Click="MenuItem_Click"/>
                            <!--<toolkit:MenuItem Header="Remove " Click="MenuItem_Click"/>-->
                        </toolkit:ContextMenu>
                    </toolkit:ContextMenuService.ContextMenu>
                    <Grid  HorizontalAlignment="Left" Width="30" Margin="0,0,0,2" Background="#FF0195D5" Height="118">
                        <!--<Grid.Background>
                            <ImageBrush ImageSource="Images/Text-ALU.png" Stretch="Fill" />
                        </Grid.Background>-->
                        <TextBlock  x:Name="txtDate" TextWrapping="Wrap" Text="{Binding Path=announcementDate}" RenderTransformOrigin="0.5,0.5" Margin="-43.169,44.001,-43.831,0" UseLayoutRounding="False" d:LayoutRounding="Auto" TextAlignment="Center" Height="30" VerticalAlignment="Top" Width="117">
                            <TextBlock.RenderTransform>
                                <CompositeTransform Rotation="-90"/>
                            </TextBlock.RenderTransform>
                        </TextBlock>
                    </Grid>
                    <Grid HorizontalAlignment="Left" Width="5" Height="120"/>
                    <StackPanel   Orientation="Vertical" VerticalAlignment="Top" Width="432" Height="114">
                        <TextBlock x:Name="txtTitle" Height="27" TextWrapping="Wrap" Text="{Binding Path=announcementTitle}"   FontSize="18.667" HorizontalAlignment="Left" Width="432" FontWeight="Bold" />
                        <StackPanel Orientation="Horizontal" Width="432" Height="27">
                            <TextBlock x:Name="txtBy" FontWeight="Bold" Height="27" TextWrapping="Wrap" Text="{Binding Path=announcementBy}"  FontSize="18.667" Width="399"/>
                            <Image x:Name="imgArrow" Width="25" Source="Images/Go-In-Arrow.png" Height="25" Margin="5,0,0,0"/>
                        </StackPanel>
                        <StackPanel Orientation="Horizontal" Width="433" Height="60">
                            <TextBlock x:Name="txtDesc" FontWeight="Bold" Height="58" TextWrapping="Wrap" Text="{Binding Path=announcementShortDescription}" FontSize="18.667" Width="371"/>
                            <TextBlock x:Name="txtID" Height="56" Text="{Binding Path=announcementID}"  TextWrapping="Wrap" Foreground="Black" FontSize="18.667" Width="8" Visibility="Collapsed"/>
                            <Image x:Name="imgType" Width="35" Source="{Binding Path=announcementTypeImage}" Height="40" Margin="27,20,0,0" d:LayoutOverrides="Height"/>
                        </StackPanel>
                    </StackPanel>
                </StackPanel>

            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>

我想使用c＃在后面的代碼中使用x：name txtDesc更改textblocxk的前景色

我在嘗試

txtDesc.Foreground = Brushes.White;

但是它不認識它，那么如何實現呢？ 還有沒有其他方法可以使用綁定更改前景色

Answer 1

嘗試這個：

Xaml：

<TextBlock x:Name="txtDesc" FontWeight="Bold" Height="58" TextWrapping="Wrap"  Text="{Binding Path=announcementShortDescription}" FontSize="18.667" Width="371" Foreground="Yellow"/>

CS：

txtDesc.Foreground = new SolidColorBrush(Colors.Yellow);

Answer 2

正如我在評論中說的那樣，您的代碼未編譯的原因是因為您的TextBlock是ListBox的DataTemplate的一部分，而不是頁面本身上的對象。 因此，您希望存在多個實例。 您如何僅用一個標識符就能識別它們呢？

您稍后在注釋中提到，您要做的是根據項目的屬性值更改每個列表項目中TextBlock的顏色。 有幾種方法可以做到這一點。

您可以使用Blend行為：

<ListBox.ItemTemplate>
    <DataTemplate>
        <TextBlock Text="{Binding announcementShortDescription}" >
            <Interactivity:Interaction.Behaviors>
                <Core:DataTriggerBehavior Value="1" Binding="{Binding itemread}">
                    <Core:ChangePropertyAction PropertyName="Foreground">
                        <Core:ChangePropertyAction.Value>
                            <SolidColorBrush Color="Blue"/>
                        </Core:ChangePropertyAction.Value>
                    </Core:ChangePropertyAction>
                </Core:DataTriggerBehavior>
            </Interactivity:Interaction.Behaviors>
        </TextBlock>
    </DataTemplate>
</ListBox.ItemTemplate>

不過，我的首選是使用值轉換器。 就像是：

class ItemReadToColorConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, string language)
    {
        int val = (int)value;

        return val == 0 ? new SolidColorBrush(Colors.Black) : new SolidColorBrush(Colors.Blue);
    }

    public object ConvertBack(object value, Type targetType, object parameter, string language)
    {
        throw new NotImplementedException();
    }
}

在XAML中：

<ListBox x:Name="list">
    <ListBox.Resources>
        <local:ItemReadToColorConverter x:Key="conv" />
    </ListBox.Resources>
    <ListBox.ItemTemplate>
        <DataTemplate>
            <TextBlock Foreground="{Binding itemread, Converter={StaticResource conv}}" Text="{Binding announcementShortDescription}" />
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>