在 VBA 中调用类函数时出错

Question

I have this class module inside my Access database:

Option Compare Database

Public Event BeforeCalc()

Public Sub Calculate(ByVal i As Integer, ByVal y As Integer)
    RaiseEvent BeforeCalc
    Calculate = i + y
End Sub


Private Sub Class_Initialize()
    Debug.Print "Inside construcotr"
End Sub

Then, inside a custom form:

Option Compare Database

Private WithEvents math As MyMath

Private Sub btnCalculate_Click()
    Dim result As Integer
    Set result = math.Calculate(CInt(txtI.Text), CInt(txtY.Text))
End Sub

Private Sub Form_Load()
    Set math = New MyMath
End Sub

Private Sub math_BeforeCalc()
    MsgBox "About to Calc!", vbInformation
End Sub

When I click the form button btnCalculate I got this error at math.Calculate:

"Compile error. Expected function or variable."

What's wrong with my code?

Answer 1

Since it is a function so it should return something, in your case an integer and also you should specify the Function keyword.

replace the code :

Public Sub Calculate(ByVal i As Integer, ByVal y As Integer)
     RaiseEvent BeforeCalc
     Calculate = i + y
End Sub

with :

Public Function Calculate(ByVal i As Integer, ByVal y As Integer) as Integer
    RaiseEvent BeforeCalc
    Calculate = i + y
End Sub

Answer 2

You have defined Calculate as a Sub, try defining it as a Function:

Public Function Calculate(ByVal i As Integer, ByVal y As Integer) as Integer
    RaiseEvent BeforeCalc
    Calculate = i + y
End Function

Also, don't set the result:

Private Sub btnCalculate_Click()
    Dim result As Integer
    result = math.Calculate(CInt(txtI.Text), CInt(txtY.Text))
End Sub