C#中实现左侧折叠导航菜单的示例代码

// 初始化菜单面板
Panel menuPanel = new Panel {
    Dock = DockStyle.Left,
    Width = 200,
    BackColor = Color.FromArgb(240, 240, 240)
};

// 创建折叠按钮
Button toggleBtn = new Button {
    Text = "☰ 菜单",
    Dock = DockStyle.Top,
    Font = new Font("微软雅黑", 10, FontStyle.Bold),
    BackColor = Color.DimGray
};
toggleBtn.Click += (s, e) => {
    menuPanel.Width = menuPanel.Width == 200 ? 60 : 200;
    this.Invalidate(); // 触发重绘
};

// 添加到窗体
this.Controls.Add(toggleBtn);
this.Controls.Add(menuPanel);

Timer aniTimer = new Timer { Interval = 20 };
int targetWidth = 200;
int currentWidth = 60;

void AnimateResize() {
    if (menuPanel.Width < targetWidth) {
        menuPanel.Width += 5;
        toggleBtn.Text = "☰ 菜单";
    } else if (menuPanel.Width > currentWidth) {
        menuPanel.Width -= 5;
        toggleBtn.Text = "▶ 内容";
    } else {
        aniTimer.Stop();
    }
}

// 触发时启动动画
toggleBtn.Click += (s, e) => {
    targetWidth = menuPanel.Width == 200 ? 60 : 200;
    currentWidth = menuPanel.Width;
    aniTimer.Start();
};

TreeNode node1 = new TreeNode("系统管理", 0, 0);
TreeNode node1_1 = new TreeNode("用户管理", 1, 1);
TreeNode node1_2 = new TreeNode("权限设置", 2, 2);
node1.Nodes.Add(node1_1);
node1.Nodes.Add(node1_2);

treeView1.Nodes.Add(node1);
treeView1.ExpandAll();

<Window x:Class="FoldableMenu.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        Title="折叠导航菜单" Height="450" Width="800">
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto"/>
            <ColumnDefinition Width="*"/>
        </Grid.ColumnDefinitions>

        <!-- 左侧菜单 -->
        <DockPanel x:Name="MenuDock" Grid.Column="0" Width="200" Background="#2D2D30">
            <Button DockPanel.Dock="Top" 
                    Content="☰ 菜单" 
                    Foreground="White" 
                    FontSize="16"
                    Margin="5"
                    Click="ToggleMenu"/>
            
            <Expander Header="系统管理" IsExpanded="False">
                <Expander.HeaderTemplate>
                    <DataTemplate>
                        <TextBlock Text="{Binding}" 
                                   Foreground="LightBlue" 
                                   Margin="5"/>
                    </DataTemplate>
                </Expander.HeaderTemplate>
                <ListBox>
                    <ListBoxItem Content="用户管理"/>
                    <ListBoxItem Content="权限设置"/>
                </ListBox>
            </Expander>
        </DockPanel>

        <!-- 主内容区 -->
        <Grid Grid.Column="1">
            <TextBlock Text="主内容区域" 
                       FontSize="24" 
                       VerticalAlignment="Center" 
                       HorizontalAlignment="Center"/>
        </Grid>
    </Grid>
</Window>

public class MenuModel : INotifyPropertyChanged {
    private bool _isExpanded;
    public bool IsExpanded {
        get => _isExpanded;
        set {
            _isExpanded = value;
            OnPropertyChanged(nameof(IsExpanded));
        }
    }
    
    // 实现INotifyPropertyChanged接口
    public event PropertyChangedEventHandler PropertyChanged;
    protected void OnPropertyChanged(string prop) {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(prop));
    }
}

// XAML绑定
<Expander Header="系统管理" IsExpanded="{Binding IsExpanded}">

<Window.Resources>
    <Storyboard x:Key="CollapseAnim">
        <DoubleAnimation Storyboard.TargetName="MenuDock" 
                         Storyboard.TargetProperty="Width"
                         From="200" To="60" Duration="0:0:0.3"/>
    </Storyboard>
    
    <Storyboard x:Key="ExpandAnim">
        <DoubleAnimation Storyboard.TargetName="MenuDock" 
                         Storyboard.TargetProperty="Width"
                         From="60" To="200" Duration="0:0:0.3"/>
    </Storyboard>
</Window.Resources>

// 触发动画
private void ToggleMenu(object sender, RoutedEventArgs e) {
    Storyboard sb = (MenuDock.Width == 200) 
        ? (Storyboard)FindResource("CollapseAnim") 
        : (Storyboard)FindResource("ExpandAnim");
    sb.Begin(this);
}

<Style TargetType="Button">
    <Setter Property="Background" Value="Transparent"/>
    <Style.Triggers>
        <Trigger Property="IsMouseOver" Value="True">
            <Setter Property="Background" Value="#404040"/>
        </Trigger>
    </Style.Triggers>
</Style>

// 保存状态
Properties.Settings.Default.MenuWidth = menuDock.Width;
Properties.Settings.Default.Save();

// 恢复状态
menuDock.Width = Properties.Settings.Default.MenuWidth;

private void Form_Resize(object sender, EventArgs e) {
    menuPanel.Width = this.ClientSize.Width / 4;
}