类函数中的错误 91

Posted 2023-05-07

【中文标题】类函数中的错误 91

【英文标题】：Error 91 in class function

【发布时间】：2015-04-10 18:32:35

【问题描述】：

使用 Access 2010，我正在收集信息并将其放到 Excel 电子表格中。当我运行下面的代码时，我得到了

运行时错误“91”：对象变量或未设置块

在我的课堂上这一行Set Cci = ChartColorItems(ColorID)Public Function GetRGB(ByRef ColorID As String) As Integer

“ChartColors”类：

Option Compare Database
Option Explicit

Private pChartColorItems As Collection

Public Property Get ChartColorItems() As Collection
  Set ChartColorItems = pChartColorItems
End Property
Public Property Set ChartColorItems(ByRef lChartColorItem As Collection)
  Set pChartColorItems = lChartColorItem
End Property

Public Function GetRGB(ByRef ColorID As String) As Integer
  Dim Cci As ChartColorItem
  Dim x As Integer

'---------------------------------------------------
'Error happens here:      
  Set Cci = ChartColorItems(ColorID)
'---------------------------------------------------
  x = RGB(Cci.Red, Cci.Green, Cci.Blue)
  GetRGB = x
  Set Cci = Nothing

End Function

Private Sub Class_Initialize()

  Dim Cci As ChartColorItem
  Dim Colors As Collection

  Set Colors = New Collection

  Set Cci = New ChartColorItem
  Cci.Red = 149
  Cci.Green = 55
  Cci.Blue = 53
  Cci.ColorID = "Pie1"
  Colors.Add Cci, Key:=Cci.ColorID
  Set Cci = Nothing

  Set Cci = New ChartColorItem
  Cci.Red = 148
  Cci.Green = 138
  Cci.Blue = 84
  Cci.ColorID = "Pie2"
  Colors.Add Cci, Key:=Cci.ColorID
  Set Cci = Nothing

End Sub

以及 ChartColorItem 类：

Option Compare Database
Option Explicit

Private pColorID As String
Private pRed As Integer
Private pGreen As Integer
Private pBlue As Integer

Public Property Get ColorID() As String
  ColorID = pColorID
End Property
Public Property Let ColorID(ByRef x As String)
  pColorID = x
End Property

Public Property Get Red() As Integer
  Red = pRed
End Property
Public Property Let Red(ByRef x As Integer)
  pRed = x
End Property

Public Property Get Green() As Integer
  Green = pGreen
End Property
Public Property Let Green(ByRef x As Integer)
  pGreen = x
End Property

Public Property Get Blue() As Integer
  Blue = pBlue
End Property
Public Property Let Blue(ByRef x As Integer)
  pBlue = x
End Property

当我调试时，代码通过ChartColorItems() getter 就好了，错误发生在End Function 之后，并把我放在上面提到的那一行。

这与我本周早些时候编写的一些代码非常相似，主要区别在于我使用 Class_Initialize 子填充我的 ChartColors，因为我试图存储一组固定的颜色，而我之前的代码正在收集数据并以更“正常”的方式将其插入到类中。

【问题讨论】：

不...如何/为什么看起来不正确？这正是我本周早些时候编写另一个函数的方式。

抱歉没有看到所有代码，我认为它的末尾是Set Cci = Nothing

@StevenMartin 哪个？在Class_Initialize 或GetRGB？

好吧，您先公开声明，然后私下声明，然后将其设置为空，因此当对象不存在时会出现 91 错误

【参考方案1】：

您在模块级别将私有集合定义为pCharColorItems，但您从未在类的初始化方法中对其进行初始化。相反，您使用本地范围的 Colors 集合变量。

Private Sub Class_Initialize()

  Dim Cci As ChartColorItem
  Dim Colors As Collection

  Set Colors = New Collection

您需要改用pChartColorItems。

Private Sub Class_Initialize()

  Dim Cci As ChartColorItem
  Dim Colors As Collection

  Set pChartColorItems = New Collection

  Set Cci = New ChartColorItem
  Cci.Red = 149
  Cci.Green = 55
  Cci.Blue = 53
  Cci.ColorID = "Pie1"
  pChartColorItems.Add Cci, Key:=Cci.ColorID
  Set Cci = Nothing

  Set Cci = New ChartColorItem
  Cci.Red = 148
  Cci.Green = 138
  Cci.Blue = 84
  Cci.ColorID = "Pie2"
  pChartColorItems.Add Cci, Key:=Cci.ColorID
  Set Cci = Nothing

End Sub

但是GetRGB这一行还有一个bug。

 x = RGB(Cci.Red, Cci.Green, Cci.Blue)

当RGB 函数返回一个长整数时，您将x 声明为整数。 “Pie1”的值会导致溢出错误。