如何为WPF Adorner添加Tooltip？连接状态Poor时显示提示

核心思路 #

• 启用命中测试：当前代码固定设置IsHitTestVisible = false，会阻止鼠标与Adorner交互，导致Tooltip无法触发。需根据ConnectionState动态控制该属性，仅在状态为Poor时开启命中测试。
• 使用ToolTipService附加属性：WPF的ToolTipService可直接为任何UIElement附加Tooltip，无需替换原有几何图形绘制逻辑，直接在状态切换时配置即可。

修改后的代码实现 #

public enum ConnectionState
{
    Good = 0,
    Poor = 1
}

public class ConnectionStatusAdorner : Adorner
{
    const ConnectionState DEFAULT_STATE = ConnectionState.Good;

    private readonly DrawingGroup _drawingGroup;
    private readonly RecordButton _recordButton;

    public ConnectionStatusAdorner(RecordButton recordButton)
        : base(recordButton)
    {
        _recordButton = recordButton ?? throw new ArgumentNullException(nameof(recordButton));

        _drawingGroup = new DrawingGroup();
        Focusable = false;

        SetConnectionState(DEFAULT_STATE);
    }

    public void SetConnectionState(ConnectionState state)
    {
        _drawingGroup.Children.Clear();

        var indicatorBrush = ResourceHelper.GetNetworkConnectionStatusBrush(state);
        var pen = new Pen(new SolidColorBrush(Colors.White), 1.5);

        var rect = new Rect
        {
            Location = new Point(_recordButton.Width - 8, 1.5),
            Size = new Size(10, 10)
        };

        var ellipse = new EllipseGeometry(rect);
        var drawing = new GeometryDrawing(indicatorBrush, pen, ellipse);
        _drawingGroup.Children.Add(drawing);

        // 根据状态配置Tooltip与命中测试
        if (state == ConnectionState.Poor)
        {
            IsHitTestVisible = true;
            ToolTipService.SetToolTip(this, "Poor connection");
            ToolTipService.SetIsEnabled(this, true);
        }
        else
        {
            IsHitTestVisible = false;
            ToolTipService.SetToolTip(this, null);
            ToolTipService.SetIsEnabled(this, false);
        }
    }

    protected override void OnRender(DrawingContext drawingContext)
    {
        base.OnRender(drawingContext);
        drawingContext.DrawDrawing(_drawingGroup);
    }
}

说明 #

• 状态切换时，仅在Poor模式下开启Adorner的鼠标命中检测，并设置Tooltip内容；Good模式下关闭交互，避免不必要的鼠标响应。
• 保留了原有几何图形绘制逻辑，无需替换为按钮控件，符合UI设计的合理性要求。

内容的提问来源于stack exchange，提问作者Richard Gale