动态更改的 TextBlock 中的多行文本

Question

嗨，所以我正在尝试将 twitch 聊天推送到 TextBlock 中，它仅使用带有文本块的 mvvm 就可以正常工作，但现在我想实际为用户名着色，但不知道如何制作这个多行，因为我拥有它的方式现在它只是替换了以前的消息，所以我需要帮助才能继续前进。谢谢！\

Xaml：

<TextBlock Grid.Column="1" Grid.Row="1" TextWrapping="Wrap" Background="Gainsboro" FontSize="14" Text="" Margin="5,5,5,5">
            <Run Text="{Binding Username, Mode=OneWay}" Foreground="{Binding UsernameColor, Mode=OneWay}" />
            <Run Text="{Binding Message, Mode=OneWay}" />
</TextBlock>

事件：

private void Client_OnMessageReceived(object sender, OnMessageReceivedArgs e)
        {
            Username = $"{e.ChatMessage.DisplayName}:";
            Message = e.ChatMessage.Message;
            UsernameColor = e.ChatMessage.ColorHex;
        }

所以问题是我希望它是多行的，而不是每次通过消息时都替换运行。

Answer 1

我认为您采用了错误的方法。您必须将聊天视为消息的集合。您希望在每条消息进入时单独显示它们。这需要使用ListBox，其中每个项目代表一条单独的消息：

ChatMessage.cs

class ChatMessage : INotifyPropertyChanged
{
  private string username;
  public string Username
  {
    get => this.username;
    set
    {
      this.username = value;
      OnPropertyChanged();
    }
  }

  private string message;
  public string Message
  {
    get => this.message;
    set
    {
      this.message = value;
      OnPropertyChanged();
    }
  }

  private string colorValue;
  public string ColorValue
  {
    get => this.colorValue;
    set
    {
      this.colorValue = value;
      OnPropertyChanged();
    }
  }

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

ViewModel.cs

class ViewModel : INotifyPropertyChanged
{
  public ObservableCollection<ChatMessage> Messages { get; set; }

  private void Client_OnMessageReceived(object sender, OnMessageReceivedArgs e)
  {
    var chatMessage = new ChatMessage
    { 
      Username = $"{e.ChatMessage.DisplayName}:",
      Message = e.ChatMessage.Message
      UsernameColor = e.ChatMessage.ColorHex
    }
    this.Messages.Add(chatMessage);
  }

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

MainWindow.xaml

<Window>
  <Window.DataContext>
    <ViewModel />
  <Window.DataContext>

  <ListBox ItemsSource="{Binding Messages}"
           IsHitTestVisible="False">
    <ListBox.ItemTemplate>
      <DataTemplate DataType="{x:Type ChatMessage}">
        <StackPanel Orientation="Horizonatal">
          <TextBlock Text="{Binding Username}" 
                     Foreground="{Binding ColorValue}" />
          <TextBlock Text="{Binding Message}" />
        </StackPanel>
      </DataTemplate >
    </ListBox.ItemTemplate>
  </ListBox ItemsSource="{Binding Messages}">
</Window>