feat(clsBOMManager): add optional autoFallback param

Added the `autoFallback` optional parameter to `GetMaterialsByModel`.
This flag controls whether the search automatically descends to
subcategories when no matches are found in the target category.

- Defaults to True to maintain previous recursive behavior.
- When False, the search is restricted strictly to the specified category.
- Updated documentation with usage examples and logic explanations.

VBA/Modules/modModelParserExamples.bas

@@ -374,4 +374,129 @@ Sub Example5_ValidateMaterialConditions()
     wsValidation.Columns("A:D").AutoFit
 
     MsgBox "条件验证完成！", vbInformation
+End Sub
+
+' ========================================
+' 示例6: 对比启用/禁用自动降级的效果
+' ========================================
+Sub Example6_CompareAutoFallback()
+    Dim bomMgr As New clsBOMManager
+    Dim wsConfig As Worksheet
+    Dim wsPlatform As Worksheet
+
+    ' 加载配置
+    Set wsConfig = ThisWorkbook.Worksheets("领料配置")
+    Set wsPlatform = ThisWorkbook.Worksheets("平台配置清单")
+    bomMgr.LoadData wsConfig, wsPlatform
+
+    ' 产品型号（使用可能导致类别缺失的型号）
+    Dim modelStr As String
+    modelStr = "YTHN-100.A0.532.M203.M17.Y3|BP-095.2312.M16.PA3"
+
+    ' 创建对比结果表
+    Dim wsCompare As Worksheet
+    On Error Resume Next
+    Application.DisplayAlerts = False
+    ThisWorkbook.Worksheets("降级模式对比").Delete
+    Application.DisplayAlerts = True
+    On Error GoTo 0
+
+    Set wsCompare = ThisWorkbook.Worksheets.Add
+    wsCompare.Name = "降级模式对比"
+
+    ' 表头
+    Dim row As Long
+    row = 1
+    wsCompare.Cells(row, 1).value = "型号"
+    wsCompare.Cells(row, 2).value = modelStr
+    row = row + 2
+
+    ' 测试1: 启用自动降级
+    wsCompare.Cells(row, 1).value = "模式1: 启用自动降级 (autoFallback=True)"
+    wsCompare.Cells(row, 1).Font.Bold = True
+    row = row + 1
+
+    wsCompare.Cells(row, 1).value = "类别"
+    wsCompare.Cells(row, 2).value = "代号"
+    wsCompare.Cells(row, 3).value = "名称"
+    wsCompare.Cells(row, 4).value = "数量"
+    wsCompare.Cells(row, 5).value = "选择条件"
+    wsCompare.Range("A" & row & ":E" & row).Font.Bold = True
+    row = row + 1
+
+    Dim materials As collection
+    Dim mat As clsMaterialItem
+    Dim i As Long
+
+    ' 获取启用自动降级的物料
+    Set materials = bomMgr.GetMaterialsByModel(modelStr, "部件", True)
+
+    If materials.Count = 0 Then
+        wsCompare.Cells(row, 1).value = "(无物料)"
+        row = row + 1
+    Else
+        For i = 1 To materials.Count
+            Set mat = materials(i)
+            wsCompare.Cells(row, 1).value = mat.Category
+            wsCompare.Cells(row, 2).value = mat.code
+            wsCompare.Cells(row, 3).value = mat.Name
+            wsCompare.Cells(row, 4).value = mat.Quantity
+            wsCompare.Cells(row, 5).value = IIf(mat.Condition = "", "(无)", mat.Condition)
+            row = row + 1
+        Next i
+    End If
+
+    row = row + 1
+
+    ' 测试2: 禁用自动降级
+    wsCompare.Cells(row, 1).value = "模式2: 禁用自动降级 (autoFallback=False)"
+    wsCompare.Cells(row, 1).Font.Bold = True
+    row = row + 1
+
+    wsCompare.Cells(row, 1).value = "类别"
+    wsCompare.Cells(row, 2).value = "代号"
+    wsCompare.Cells(row, 3).value = "名称"
+    wsCompare.Cells(row, 4).value = "数量"
+    wsCompare.Cells(row, 5).value = "选择条件"
+    wsCompare.Range("A" & row & ":E" & row).Font.Bold = True
+    row = row + 1
+
+    ' 获取禁用自动降级的物料
+    Set materials = bomMgr.GetMaterialsByModel(modelStr, "部件", False)
+
+    If materials.Count = 0 Then
+        wsCompare.Cells(row, 1).value = "(无物料 - 因为禁用降级)"
+        wsCompare.Cells(row, 2).value = "说明"
+        wsCompare.Cells(row, 3).value = "当父类别无匹配物料时,不会降级到子类别查找"
+        row = row + 1
+    Else
+        For i = 1 To materials.Count
+            Set mat = materials(i)
+            wsCompare.Cells(row, 1).value = mat.Category
+            wsCompare.Cells(row, 2).value = mat.code
+            wsCompare.Cells(row, 3).value = mat.Name
+            wsCompare.Cells(row, 4).value = mat.Quantity
+            wsCompare.Cells(row, 5).value = IIf(mat.Condition = "", "(无)", mat.Condition)
+            row = row + 1
+        Next i
+    End If
+
+    ' 添加说明
+    row = row + 1
+    wsCompare.Cells(row, 1).value = "说明:"
+    wsCompare.Cells(row, 1).Font.Bold = True
+    row = row + 1
+    wsCompare.Cells(row, 1).value = "• autoFallback=True (默认): 当""部件""类别无匹配物料时,自动降级到子类别""接头""、""弹性元件""等查找"
+    row = row + 1
+    wsCompare.Cells(row, 1).value = "• autoFallback=False: 仅在""部件""类别查找,即使有子类别也不降级,可能返回空集合"
+
+    ' 格式化
+    wsCompare.Columns("A:E").AutoFit
+    wsCompare.Range("A1").Font.Bold = True
+
+    MsgBox "降级模式对比完成！" & vbCrLf & _
+           "请查看工作表: 降级模式对比" & vbCrLf & vbCrLf & _
+           "启用降级: " & bomMgr.GetMaterialsByModel(modelStr, "部件", True).Count & " 个物料" & vbCrLf & _
+           "禁用降级: " & bomMgr.GetMaterialsByModel(modelStr, "部件", False).Count & " 个物料", _
+           vbInformation
 End Sub