fix: keep crosshair visible for explicitly bound band axes

common/changes/@visactor/vchart/fix-crosshair-binding-axes_20260807.json

@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "packageName": "@visactor/vchart",
+      "comment": "fix: preserve crosshair visibility for explicitly bound multiple band axes (Issue #4127)",
+      "type": "patch"
+    }
+  ],
+  "packageName": "@visactor/vchart",
+  "email": "biukam.w@gmail.com"
+}

packages/vchart/__tests__/unit/core/vchart-event.test.ts

@@ -38,6 +38,8 @@ type StageEventListener = {
 };
 
 type CrosshairStateForTest = {
+  enable?: boolean;
+  _layoutCrosshair?: (x: number, y: number) => void;
   _stateByField?: {
     xField?: {
       currentValue?: Map<unknown, unknown>;
@@ -522,6 +524,69 @@ describe('vchart event test', () => {
     removeDom(lineContainer);
   });
 
+  it('should keep crosshair enabled when bound to top and bottom band axes', () => {
+    const crosshairContainer = createDiv();
+    const crosshairDom = createDiv(crosshairContainer);
+    crosshairDom.id = 'multiple-crosshair-axis-container';
+    crosshairContainer.style.position = 'fixed';
+    crosshairContainer.style.width = '500px';
+    crosshairContainer.style.height = '500px';
+    crosshairContainer.style.top = '0px';
+    crosshairContainer.style.left = '0px';
+
+    const chart = new VChart(
+      {
+        type: 'common',
+        data: {
+          id: 'data',
+          values: [
+            { x: 'Mon', type: 'Breakfast', y: 15 },
+            { x: 'Mon', type: 'Lunch', y: 25 },
+            { x: 'Tue', type: 'Breakfast', y: 12 },
+            { x: 'Tue', type: 'Lunch', y: 30 }
+          ]
+        },
+        series: [
+          {
+            type: 'bar',
+            dataId: 'data',
+            xField: ['x', 'type'],
+            yField: 'y',
+            seriesField: 'type'
+          }
+        ],
+        axes: [
+          { orient: 'left' },
+          { orient: 'bottom', type: 'band' },
+          { orient: 'top', type: 'band' },
+          { orient: 'top', type: 'band' }
+        ],
+        crosshair: {
+          xField: {
+            visible: true,
+            bindingAxesIndex: [1, 2]
+          }
+        }
+      } as ICommonChartSpec,
+      { dom: crosshairDom, animation: false }
+    );
+
+    try {
+      chart.renderSync();
+      const crosshair = chart.getComponents().find(component => component.type === 'cartesianCrosshair') as
+        | CrosshairStateForTest
+        | undefined;
+
+      crosshair?._layoutCrosshair?.(250, 250);
+
+      expect(crosshair?.enable).toBe(true);
+      expect(Array.from(crosshair?._stateByField?.xField?.currentValue?.keys() ?? [])).toEqual([1, 2]);
+    } finally {
+      chart.release();
+      removeDom(crosshairContainer);
+    }
+  });
+
   it('should fire tooltipRelease before release chart', () => {
     const handleTooltipRelease = jest.fn();
     vchart.on('tooltipRelease', handleTooltipRelease);

packages/vchart/src/component/crosshair/base.ts

@@ -106,17 +106,23 @@ export abstract class BaseCrossHair<T extends ICartesianCrosshairSpec | IPolarCr
    * @returns
    */
   protected _setAllAxisValues(axisMap: IAxisInfo<IAxis>, point: IPoint, field: string): boolean {
-    // 首先不能存在两个离散轴
+    // 未显式绑定轴时，同方向的多个离散轴无法确定唯一的维度位置；显式绑定表示调用方已选择这些轴。
     let discrete = false;
+    let multipleDiscreteAxes = false;
+    const bindingAxesIndex = get(this._spec, `${field}.bindingAxesIndex`);
+    const hasExplicitBinding = isArray(bindingAxesIndex) && bindingAxesIndex.length > 0;
     axisMap.forEach(item => {
       if (isDiscrete(item.axis.getScale().type)) {
         if (!discrete) {
           discrete = true;
         } else {
-          this.enable = false;
+          multipleDiscreteAxes = true;
         }
       }
     });
+    if (multipleDiscreteAxes && !hasExplicitBinding) {
+      this.enable = false;
+    }
     if (!this.enable) {
       return false;
     }