Private Sub 權(quán)重_KeyDown(KeyCode As Integer, Shift As Integer)
    If KeyCode <> vbKeyReturn And KeyCode <> vbKeyUp And KeyCode <> vbKeyDown And vbKeyTab Then Exit Sub    
    權(quán)重.Text = M1.CalculateExpression(權(quán)重.Text)
End Sub

'公共函數(shù)
Function CalculateExpression(Expression As Variant) As Variant   '當Expression為"=","+","-"號開頭時,計算它的表達式,并返回結(jié)果
    CalculateExpression = Expression
    Dim sE As String
    sE = Left(Expression, 1)
    If Not ("=+-" Like "*" & sE & "*") Then Exit Function
    Dim result As Variant
    On Error GoTo err
    Select Case sE
        Case "=", "+"
            result = Eval(MID(Expression, 2))
        Case "-"
            result = Eval(MID(Expression, 1))
    End Select
    
    CalculateExpression = result
    Exit Function
err:
    'Empty
End Function