【WPF】实现类似QQ聊天消息的界面

最近公司有个项目,是要求实现类似 QQ 聊天这种功能的。

如下图

Snipaste_2019-02-19_19-33-22

这没啥难的,稍微复杂的也就表情的解析而已。

表情在传输过程中的实现参考了新浪微博,采用半角中括号代表表情的方式。例如:“abc[doge]def”就会显示 abc,然后一个2018new_doge02_org,再 def。

于是动手就干。

 

创建一个模板控件来进行封装,我就叫它 ChatMessageControl,有一个属性 Text,表示消息内容。内部使用一个 TextBlock 来实现。

于是博主三下五除二就写出了以下代码:

C#

[TemplatePart(Name = TextBlockTemplateName, Type = typeof(TextBlock))]
public class ChatMessageControl : Control
{
    public static readonly DependencyProperty TextProperty =
        DependencyProperty.Register(nameof(Text), typeof(string), typeof(ChatMessageControl), new PropertyMetadata(default(string), OnTextChanged));

    private const string TextBlockTemplateName = "PART_TextBlock";

    private static readonly Dictionary<string, string> Emotions = new Dictionary<string, string>
    {
        ["doge"] = "pack://application:,,,/WpfQQChat;component/Images/doge.png",
        ["喵喵"] = "pack://application:,,,/WpfQQChat;component/Images/喵喵.png"
    };

    private TextBlock _textBlock;

    static ChatMessageControl()
    {
        DefaultStyleKeyProperty.OverrideMetadata(typeof(ChatMessageControl), new FrameworkPropertyMetadata(typeof(ChatMessageControl)));
    }

    public string Text
    {
        get => (string)GetValue(TextProperty);
        set => SetValue(TextProperty, value);
    }

    public override void OnApplyTemplate()
    {
        _textBlock = (TextBlock)GetTemplateChild(TextBlockTemplateName);

        UpdateVisual();
    }

    private static void OnTextChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var obj = (ChatMessageControl)d;

        obj.UpdateVisual();
    }

    private void UpdateVisual()
    {
        if (_textBlock == null)
        {
            return;
        }

        _textBlock.Inlines.Clear();

        var buffer = new StringBuilder();
        foreach (var c in Text)
        {
            switch (c)
            {
                case '[':
                    _textBlock.Inlines.Add(buffer.ToString());
                    buffer.Clear();
                    buffer.Append(c);
                    break;

                case ']':
                    var current = buffer.ToString();
                    if (current.StartsWith("["))
                    {
                        var emotionName = current.Substring(1);
                        if (Emotions.ContainsKey(emotionName))
                        {
                            var image = new Image
                            {
                                Width = 16,
                                Height = 16,
                                Source = new BitmapImage(new Uri(Emotions[emotionName]))
                            };
                            _textBlock.Inlines.Add(new InlineUIContainer(image));

                            buffer.Clear();
                            continue;
                        }
                    }

                    buffer.Append(c);
                    _textBlock.Inlines.Add(buffer.ToString());
                    buffer.Clear();
                    break;

                default:
                    buffer.Append(c);
                    break;
            }
        }

        _textBlock.Inlines.Add(buffer.ToString());
    }
}

因为这篇博文只是个演示,这里博主就只放两个表情好了,并且耦合在这个控件里。

XAML

<Style TargetType="local:ChatMessageControl">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="local:ChatMessageControl">
                <TextBlock x:Name="PART_TextBlock"
                           TextWrapping="Wrap" />
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

没啥好说的,就是包了一层而已。

效果:

Snipaste_2019-02-19_20-11-40

自我感觉良好,于是乎博主就提交代码,发了个版本到测试环境了。

 

但是,第二天,测试却给博主提了个 bug。消息无法选择、复制。

17686

在 UWP 里,TextBlock 控件是有 IsTextSelectionEnabled 属性的,然而 WPF 并没有。这下头大了,于是博主去查了一下 StackOverflow,大佬们回答都是说用一个 IsReadOnly 为 True 的 TextBox 来实现。因为我这里包含了表情,所以用 RichTextBox 来实现吧。不管行不行,先试试再说。

在原来的代码上修改一下,反正表情解析一样的,但这里博主为了方便写 blog,就新开一个控件好了。

C#

[TemplatePart(Name = RichTextBoxTemplateName, Type = typeof(RichTextBox))]
public class ChatMessageControlV2 : Control
{
    public static readonly DependencyProperty TextProperty =
        DependencyProperty.Register(nameof(Text), typeof(string), typeof(ChatMessageControlV2), new PropertyMetadata(default(string), OnTextChanged));

    private const string RichTextBoxTemplateName = "PART_RichTextBox";

    private static readonly Dictionary<string, string> Emotions = new Dictionary<string, string>
    {
        ["doge"] = "pack://application:,,,/WpfQQChat;component/Images/doge.png",
        ["喵喵"] = "pack://application:,,,/WpfQQChat;component/Images/喵喵.png"
    };

    private RichTextBox _richTextBox;

    static ChatMessageControlV2()
    {
        DefaultStyleKeyProperty.OverrideMetadata(typeof(ChatMessageControlV2), new FrameworkPropertyMetadata(typeof(ChatMessageControlV2)));
    }

    public string Text
    {
        get => (string)GetValue(TextProperty);
        set => SetValue(TextProperty, value);
    }

    public override void OnApplyTemplate()
    {
        _richTextBox = (RichTextBox)GetTemplateChild(RichTextBoxTemplateName);

        UpdateVisual();
    }

    private static void OnTextChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var obj = (ChatMessageControlV2)d;

        obj.UpdateVisual();
    }

    private void UpdateVisual()
    {
        if (_richTextBox == null)
        {
            return;
        }

        _richTextBox.Document.Blocks.Clear();

        var paragraph = new Paragraph();

        var buffer = new StringBuilder();
        foreach (var c in Text)
        {
            switch (c)
            {
                case '[':
                    paragraph.Inlines.Add(buffer.ToString());
                    buffer.Clear();
                    buffer.Append(c);
                    break;

                case ']':
                    var current = buffer.ToString();
                    if (current.StartsWith("["))
                    {
                        var emotionName = current.Substring(1);
                        if (Emotions.ContainsKey(emotionName))
                        {
                            var image = new Image
                            {
                                Width = 16,
                                Height = 16,
                                Source = new BitmapImage(new Uri(Emotions[emotionName]))
                            };
                            paragraph.Inlines.Add(new InlineUIContainer(image));

                            buffer.Clear();
                            continue;
                        }
                    }

                    buffer.Append(c);
                    paragraph.Inlines.Add(buffer.ToString());
                    buffer.Clear();
                    break;

                default:
                    buffer.Append(c);

                    break;
            }
        }

        paragraph.Inlines.Add(buffer.ToString());

        _richTextBox.Document.Blocks.Add(paragraph);
    }
}

XAML

<Style TargetType="local:ChatMessageControlV2">
    <Setter Property="Foreground"
            Value="Black" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="local:ChatMessageControlV2">
                <RichTextBox x:Name="PART_RichTextBox"
                             MinHeight="0"
                             Background="Transparent"
                             BorderBrush="Transparent"
                             BorderThickness="0"
                             Foreground="{TemplateBinding Foreground}"
                             IsReadOnly="True">
                    <RichTextBox.Resources>
                        <ResourceDictionary>
                            <Style TargetType="Paragraph">
                                <Setter Property="Margin"
                                        Value="0" />
                                <Setter Property="Padding"
                                        Value="0" />
                                <Setter Property="TextIndent"
                                        Value="0" />
                            </Style>
                        </ResourceDictionary>
                    </RichTextBox.Resources>
                    <RichTextBox.ContextMenu>
                        <ContextMenu>
                            <MenuItem Command="ApplicationCommands.Copy"
                                      Header="复制" />
                        </ContextMenu>
                    </RichTextBox.ContextMenu>
                </RichTextBox>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

XAML 稍微复杂一点,因为我们需要让一个文本框高仿成一个文字显示控件。

 

感觉应该还行,然后跑起来之后

Snipaste_2019-02-19_20-42-13

复制是能复制了,然而我的布局呢?

79521

 

因为一时间也没想到解决办法,于是博主只能回滚代码,把 bug 先晾在那里了。

经过了几天上班带薪拉屎之后,有一天博主在厕所间玩着宝石连连消的时候突然灵光一闪。对于 TextBlock 来说,只是不能选择而已,布局是没问题的。对于 RichTextBox 来说,布局不正确是由于 WPF 在测量与布局的过程中给它分配了无限大的宽度。那么,能不能将两者结合起来,TextBlock 做布局,RichTextBox 做功能呢?想到这里,博主关掉了宝石连连消,擦上屁股,开始干活。

C#

[TemplatePart(Name = TextBlockTemplateName, Type = typeof(TextBlock))]
[TemplatePart(Name = RichTextBoxTemplateName, Type = typeof(RichTextBox))]
public class ChatMessageControlV3 : Control
{
    public static readonly DependencyProperty TextProperty =
        DependencyProperty.Register(nameof(Text), typeof(string), typeof(ChatMessageControlV3), new PropertyMetadata(default(string), OnTextChanged));

    private const string RichTextBoxTemplateName = "PART_RichTextBox";
    private const string TextBlockTemplateName = "PART_TextBlock";

    private static readonly Dictionary<string, string> Emotions = new Dictionary<string, string>
    {
        ["doge"] = "pack://application:,,,/WpfQQChat;component/Images/doge.png",
        ["喵喵"] = "pack://application:,,,/WpfQQChat;component/Images/喵喵.png"
    };

    private RichTextBox _richTextBox;
    private TextBlock _textBlock;

    static ChatMessageControlV3()
    {
        DefaultStyleKeyProperty.OverrideMetadata(typeof(ChatMessageControlV3), new FrameworkPropertyMetadata(typeof(ChatMessageControlV3)));
    }

    public string Text
    {
        get => (string)GetValue(TextProperty);
        set => SetValue(TextProperty, value);
    }

    public override void OnApplyTemplate()
    {
        _textBlock = (TextBlock)GetTemplateChild(TextBlockTemplateName);
        _richTextBox = (RichTextBox)GetTemplateChild(RichTextBoxTemplateName);

        UpdateVisual();
    }

    private static void OnTextChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var obj = (ChatMessageControlV3)d;

        obj.UpdateVisual();
    }

    private void UpdateVisual()
    {
        if (_textBlock == null || _richTextBox == null)
        {
            return;
        }

        _textBlock.Inlines.Clear();
        _richTextBox.Document.Blocks.Clear();

        var paragraph = new Paragraph();

        var buffer = new StringBuilder();
        foreach (var c in Text)
        {
            switch (c)
            {
                case '[':
                    _textBlock.Inlines.Add(buffer.ToString());
                    paragraph.Inlines.Add(buffer.ToString());
                    buffer.Clear();
                    buffer.Append(c);
                    break;

                case ']':
                    var current = buffer.ToString();
                    if (current.StartsWith("["))
                    {
                        var emotionName = current.Substring(1);
                        if (Emotions.ContainsKey(emotionName))
                        {
                            {
                                var image = new Image
                                {
                                    Width = 16,
                                    Height = 16
                                };// 占位图像不需要加载 Source 了
                                _textBlock.Inlines.Add(new InlineUIContainer(image));
                            }
                            {
                                var image = new Image
                                {
                                    Width = 16,
                                    Height = 16,
                                    Source = new BitmapImage(new Uri(Emotions[emotionName]))
                                };
                                paragraph.Inlines.Add(new InlineUIContainer(image));
                            }

                            buffer.Clear();
                            continue;
                        }
                    }

                    buffer.Append(c);
                    _textBlock.Inlines.Add(buffer.ToString());
                    paragraph.Inlines.Add(buffer.ToString());
                    buffer.Clear();
                    break;

                default:
                    buffer.Append(c);
                    break;
            }
        }

        _textBlock.Inlines.Add(buffer.ToString());
        paragraph.Inlines.Add(buffer.ToString());

        _richTextBox.Document.Blocks.Add(paragraph);
    }
}

C# 代码相当于把两者结合起来而已。

XAML

<Style TargetType="local:ChatMessageControlV3">
    <Setter Property="Foreground"
            Value="Black" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="local:ChatMessageControlV3">
                <Grid>
                    <TextBlock x:Name="PART_TextBlock"
                               Padding="6,0,6,0"
                               IsHitTestVisible="False"
                               Opacity="0"
                               TextWrapping="Wrap" />
                    <RichTextBox x:Name="PART_RichTextBox"
                                 Width="{Binding ElementName=PART_TextBlock, Path=ActualWidth}"
                                 MinHeight="0"
                                 Background="Transparent"
                                 BorderBrush="Transparent"
                                 BorderThickness="0"
                                 Foreground="{TemplateBinding Foreground}"
                                 IsReadOnly="True">
                        <RichTextBox.Resources>
                            <ResourceDictionary>
                                <Style TargetType="Paragraph">
                                    <Setter Property="Margin"
                                            Value="0" />
                                    <Setter Property="Padding"
                                            Value="0" />
                                    <Setter Property="TextIndent"
                                            Value="0" />
                                </Style>
                            </ResourceDictionary>
                        </RichTextBox.Resources>
                        <RichTextBox.ContextMenu>
                            <ContextMenu>
                                <MenuItem Command="ApplicationCommands.Copy"
                                          Header="复制" />
                            </ContextMenu>
                        </RichTextBox.ContextMenu>
                    </RichTextBox>
                </Grid>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

XAML 大体也是将两者结合起来,但是把 TextBlock 设置为隐藏(但占用布局),而 RichTextBox 则绑定 TextBlock 的宽度。

至于为啥 TextBlock 有一个左右边距为 6 的 Padding 嘛。在运行之后,博主发现,RichTextBox 的内容会离左右有一定的距离,但是没找到相关的属性能够设置,如果正在看这篇博文的你,知道相关的属性的话,可以在评论区回复一下,博主我将会万分感激。

最后是我们的效果啦。

Snipaste_2019-02-19_21-13-42

 

最后,因为现在 WPF 是开源(https://github.com/dotnet/wpf)的了,因此已经蛋疼不已的博主果断提了一个 issue(https://github.com/dotnet/wpf/issues/307),希望有遇到同样困难的小伙伴能在上面支持一下,让巨硬早日把 TextBlock 选择这功能加上。

posted @ 2019-02-19 21:19 h82258652 阅读(...) 评论(...) 编辑 收藏