如何檢查是否已選中任何單選按鈕

Question

我有4個單選按鈕，我想檢查是否已選中。

這是我的WPF代碼：

<StackPanel Background="#FF3A3A49" Grid.Column="1" Grid.Row="4">
    <RadioButton x:Name="rtnRight" GroupName="answer"  HorizontalAlignment="Center" VerticalAlignment="Top" Foreground="White" Content="value0" BorderBrush="White"/>
    <RadioButton Content="value1" GroupName="answer" HorizontalAlignment="Center" VerticalAlignment="Center" Foreground="White" />
    <RadioButton Content="value2" GroupName="answer" HorizontalAlignment="Center" VerticalAlignment="Bottom"  Foreground="White" />
    <RadioButton Content="value3" GroupName="answer" HorizontalAlignment="Center" VerticalAlignment="Bottom"  Foreground="White" />
</StackPanel>
<Button x:Name="btnNext" Grid.Column="1" Grid.Row="5" Content="Dalej" VerticalAlignment="Center" HorizontalAlignment="Center" Width="100" Height="50" Margin="0 0 0 0 " Foreground="#FFAC0303" BorderBrush="#FFC1C1C1" Background="#66FFFFFF" Click="btnNext_Click"></Button>

單擊btnNext並且未選中任何btnNext按鈕后，我想顯示一個消息對話框。 我該如何編碼？ 到目前為止，這是我的btnNext_Click函數。

private async void btnNext_Click(object sender, RoutedEventArgs e)
    {    
        if ("any radiobutton checked?")
        {
           await new Windows.UI.Popups.MessageDialog("Choose at least one answer").ShowAsync();
        }
    }

Answer 1

您可以為StackPanel指定一個名稱，然后進行如下檢查：

if (!(radioButtonStackPanel.Children.OfType<RadioButton>().Any(rb => rb.IsChecked == true)))

只需記住為StackPanel指定一個名稱即可，例如：

<StackPanel Background="#FF3A3A49" Grid.Column="1" Grid.Row="4" x:Name="radioButtonStackPanel">