VB6 - ByRef参数类型不匹配错误 - 它在哪里？

在我使用VB6的10多年里,我偶尔得到一个"ByRef参数类型不匹配"错误,我根本找不到不匹配.经过一段时间的挣扎之后,我总是以这种或那种方式强迫这种类型,但这次我想我会问.我包含了我认为可能与此有关的所有代码; 但是你现在可以跳过它并在我演示问题后引用它:

Public Type PBufferType
  Location(9) As Integer ' code location
  ValueHi(9) As Integer  ' Vhi code
  ValueLo(9) As Integer  ' Vlo code
  Locked(9) As Integer   ' State of pair
  Gamma(9) As Single     ' Gamma between this segment and next
End Type

Public GammaBuffer(1) As PBufferType ' The main data type

Public SelectedBank as Integer

Function MeasureLuxAtCode(code As Integer) As Single
  Call TestPatternForm.DrawTestWindow(3, code) 
  MeasureLuxAtCode = MeasureLux(1)
End Function

问题发生在下面."LuxMinTarget = MeasureLuxAtCode(FirstLevel)"行生成"ByRef参数类型不匹配"错误,指示FirstLevel不是整数.

Sub DetermineIdealLuxCurve()
  Dim FirstLevel, FirstDACtoMeasure As Integer
  FirstDACtoMeasure = 0
  FirstLevel = GammaBuffer(SelectedBank).Location(FirstDACtoMeasure)
  LuxMinTarget = MeasureLuxAtCode(FirstLevel)
End Sub

但是它,FirstLevel 是一个整数,不是吗？它是一个虚拟的int,它的值由一个返回int的UDT设置,那么我哪里出错？如果我强制它为这样的int:

  LuxMinTarget = MeasureLuxAtCode(Int(FirstLevel))

编译器/解释器很高兴.但我不是.

这是编译器中的一个错误还是我的密集？

问题出在这里:

Dim FirstLevel, FirstDACtoMeasure As Integer

这实际上声明FirstLevel为a Variant而不是Integer你所期望的.

这是经典的VB6陷阱!(而且你不是第一个被它咬伤的人).

每行声明一个变量可以避免这个问题:

Dim FirstLevel As Integer
Dim FirstDACtoMeasure As Integer