使用C#开发ChatGPT聊天程序

使用C#开发ChatGPT聊天程序

总体效果如下：

关键点1：无边框窗口拖动

Window中设置AllowsTransparency="True"、 Background="Transparent"以及WindowStyle="None"这样设置的话默认窗口的标题栏为不可见状态，且无法用鼠标拖动，使用windowChorme来解决

<WindowChrome.WindowChrome>
    <WindowChrome CaptionHeight="50" UseAeroCaptionButtons="False" />
</WindowChrome.WindowChrome>

关键点2：输入栏实现删除按钮

1. 定义TextBox的ControlTemplate模板（节取重要部分）

<Style x:Key="TextBoxPromote" TargetType="{x:Type TextBox}">
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type TextBox}">
                        <Border
                            x:Name="border"
                            CornerRadius="6"
                            <DockPanel LastChildFill="True">
                        	<!--新增btn按钮,并绑定Click事件-->
                                <Button
                                    x:Name="btn"
                                    Grid.Column="1"
                                    Background="White"
                                    BorderThickness="0"
                                    Click="Button_Click"
                                    Content="&#xe8d5;"
                                    DockPanel.Dock="Right"
                                    FontFamily="./img/#iconfont" />

                                <ScrollViewer
                                    x:Name="PART_ContentHost"
                                    DockPanel.Dock="Left"
                                    Focusable="false"
                                    HorizontalScrollBarVisibility="Hidden"
                                    VerticalScrollBarVisibility="Hidden" />
                            </DockPanel>
                        </Border>
                        <ControlTemplate.Triggers>
                           <!--新增DataTrigger，当Text属性部位为空时，不显示按钮，Hiddern表示不显示，但是用空格来代替按钮来保持布局，而Collapsed则是不显示且不保留空格-->
                            <DataTrigger Binding="{Binding RelativeSource={RelativeSource Self}, Path=Text}" Value="">
                                <Setter TargetName="btn" Property="Visibility" Value="Collapsed" />
                            </DataTrigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>

2. 实现Button按钮事件

private void Button_Click(object sender, RoutedEventArgs e)
{
    Button? btn = sender as Button;
    if (btn != null)
    {
        var parent = VisualTreeHelper.GetParent(btn);
        while (!(parent is TextBox))
        {
            parent = VisualTreeHelper.GetParent(parent);
        }
        TextBox txt = parent as TextBox;
        if (txt != null)
        {
            txt.Clear();
        }
    }
}

关键点3：ListBox实现聊天效果

本文使用ListBox来完成消息框的展示，因为涉及到发送和收到两种类型的消息，应该对应两种不同格式，所以会用到样式选择器

1. 定义选择器类

   public class DateTemplateSelector:DataTemplateSelector
   {
       public DataTemplate SendTemplate { get; set; }
       public DataTemplate ResTemplate { get; set; }
       public override DataTemplate SelectTemplate(object item, DependencyObject container)
       {
           Message message = (Message)item;
   
           if (message.IsSend)
           {
               return SendTemplate;
           }
           else
           {
               return ResTemplate;
           }
       }
   }
   

2. 在Windwo.Resources中定义数据模板

发送模板

<DataTemplate x:Key="chatSend">
    <StackPanel
        x:Name="SendMsg"
        Margin="0,12,20,0"
        HorizontalAlignment="Right"
        Orientation="Horizontal">
        <StackPanel Margin="0,0,10,0" Orientation="Vertical">
            <!--  消息内容  -->
            <Border
                MinWidth="50"
                MinHeight="30"
                MaxWidth="{Binding Path=ActualWidth,ElementName=borderWidth}"
                Background="#c8dd1f"
                BorderBrush="#ddd"
                BorderThickness="1"
                CornerRadius="8,0,8,8">
                <TextBox
                    MinWidth="30"
                    Margin="8"
                    VerticalAlignment="Center"
                    Background="Transparent"
                    BorderThickness="0"
                    FontSize="14"
                    IsReadOnly="True"
                    Text="{Binding Msg}"
                    TextWrapping="WrapWithOverflow" />
            </Border>
        </StackPanel>
        <!--  头像  -->
        <Border
            Width="35"
            Height="35"
            Margin="0,2,0,0"
            VerticalAlignment="Top"
            BorderThickness="0">
            <Border.Background>
                <ImageBrush ImageSource="/img/user.jpg" />
            </Border.Background>
        </Border>
    </StackPanel>
</DataTemplate>

接收模板

<DataTemplate x:Key="chatRes">
    <StackPanel
        x:Name="SendMsg"
        Margin="0,12,20,0"
        HorizontalAlignment="Right"
        Orientation="Horizontal">
        <!--  头像  -->
        <Border
                    Width="35"
                    Height="35"
                    Margin="0,2,0,0"
                    VerticalAlignment="Top"
                    BorderThickness="0">
                    <Border.Background>
                        <ImageBrush ImageSource="/img/图标ChatGPT.ico" />
                    </Border.Background>
                </Border>
        <StackPanel Margin="0,0,10,0" Orientation="Vertical">
            <!--  消息内容  -->
            <Border
                MinWidth="50"
                MinHeight="30"
                MaxWidth="{Binding Path=ActualWidth,ElementName=borderWidth}"
                Background="#c8dd1f"
                BorderBrush="#ddd"
                BorderThickness="1"
                CornerRadius="0,8,8,8">
                <TextBox
                    MinWidth="30"
                    Margin="8"
                    VerticalAlignment="Center"
                    Background="Transparent"
                    BorderThickness="0"
                    FontSize="14"
                    IsReadOnly="True"
                    MaxLength="25"
                    Text="{Binding Msg}"
                    TextWrapping="WrapWithOverflow" />
            </Border>
        </StackPanel>
    </StackPanel>
</DataTemplate>

3. 因为发送消息和接受消息的对齐方式不同，一个是左一个是右，所以要定义下ListBox.ItemContainerStyle

<Style x:Key="listViewItemStyle" TargetType="{x:Type ListBoxItem}">
    <Setter Property="FocusVisualStyle" Value="{x:Null}" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type ListBoxItem}">
                <Border
                    Name="Bd"
                    Margin="1"
                    Padding="{TemplateBinding Padding}"
                    Background="{TemplateBinding Background}"
                    BorderBrush="{TemplateBinding BorderBrush}"
                    BorderThickness="{TemplateBinding BorderThickness}"
                    SnapsToDevicePixels="true">
                    <ContentPresenter
                        Margin="1"
                        HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
                        VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
                        SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
                </Border>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
    <!--判断是否为发送，从而使用不同的对齐方式-->
    <Style.Triggers>
        <DataTrigger Binding="{Binding IsSend}" Value="True">
            <Setter Property="HorizontalContentAlignment" Value="Stretch" />
        </DataTrigger>
        <DataTrigger Binding="{Binding IsSend}" Value="False">
            <Setter Property="HorizontalContentAlignment" Value="Left" />
        </DataTrigger>
    </Style.Triggers>
</Style>

3. 为了实现ListBox始终保持下拉到最后的状态，自定义类，重写OnItemsChanged方法

class ScrollingListBox : ListBox
{
    protected override void OnItemsChanged(System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
    {
        if (e.NewItems == null) return;
        var newItemCount = e.NewItems.Count;

        if (newItemCount > 0)
            this.ScrollIntoView(e.NewItems[newItemCount - 1]);

        base.OnItemsChanged(e);
    }
}

4. XAML中设置

<!--  消息显示区  -->
<!--设置ScrollViewer.CanContentScroll="False"可以使得滚动条更加丝滑-->
<local:ScrollingListBox 
    Grid.Row="0"
    BorderBrush="#D3D3D3"
    BorderThickness="0,1,0,1"
    ItemsSource="{Binding Path=Messages, ElementName=mainWindow}"
    ScrollViewer.HorizontalScrollBarVisibility="Disabled"
    ScrollViewer.CanContentScroll="False"
    SelectionMode="Extended">
    <ListBox.ItemTemplateSelector>
        <local:DateTemplateSelector ResTemplate="{StaticResource chatRes}" SendTemplate="{StaticResource chatSend}" />
    </ListBox.ItemTemplateSelector>
    <ListBox.ItemContainerStyle>
        <Style BasedOn="{StaticResource listViewItemStyle}" TargetType="{x:Type ListBoxItem}" />
    </ListBox.ItemContainerStyle>
</local:ScrollingListBox>