执行除法时类型不匹配错误

Question

我正在尝试制作交易计算器，用户在框中添加值，然后将其除以他输入的值的总数，例如：50 + 60 + 70 / 3 所以，我希望除法文本框来计算框的数量在那里并选择了除法的数字，因此用户不必添加除法值，它将自动执行。我会附上样本

Dim total As Double
Dim text_percen As Double


total = 0
If Len(Trading_calculator1.txt_currency1.Value) > 0 Then total = total + Trading_calculator1.txt_currency1.Value

If Len(Trading_calculator1.txt_currency2.Value) > 0 Then total = total + Trading_calculator1.txt_currency2.Value

If Len(Trading_calculator1.txt_currency3.Value) > 0 Then total = total + Trading_calculator1.txt_currency3.Value

If Len(Trading_calculator1.txt_currency4.Value) > 0 Then total = total + Trading_calculator1.txt_currency4.Value

If Len(Trading_calculator1.txt_currency5.Value) > 0 Then total = total + Trading_calculator1.txt_currency5.Value

If Len(Trading_calculator1.txt_currency6.Value) > 0 Then total = total + Trading_calculator1.txt_currency6.Value

If Len(Trading_calculator1.txt_currency7.Value) > 0 Then total = total + Trading_calculator1.txt_currency7.Value

If Len(Trading_calculator1.txt_currency8.Value) > 0 Then total = total + Trading_calculator1.txt_currency8.Value

If Len(Trading_calculator1.txt_currency9.Value) > 0 Then total = total + Trading_calculator1.txt_currency9.Value

If Len(Trading_calculator1.txt_currency10.Value) > 0 Then total = total + Trading_calculator1.txt_currency10.Value

If Len(Trading_calculator1.txt_currency11.Value) > 0 Then total = total + Trading_calculator1.txt_currency11.Value

If Len(Trading_calculator1.txt_currency12.Value) > 0 Then total = total + Trading_calculator1.txt_currency12.Value

If Len(Trading_calculator1.txt_currency13.Value) > 0 Then total = total + Trading_calculator1.txt_currency13.Value



If Trading_calculator1.txt_divide.Value <> "" Then total = total / Trading_calculator1.txt_divide.Value

Trading_calculator1.text_percen = total

我尝试了上面的代码，但它给了我：

类型不匹配错误。

谁能帮忙？

Answer 1

如果没有显式类型转换，您将依赖隐式类型转换，但并非所有字符串都可以转换为双精度值。最好有一个函数接受字符串值、处理错误并返回有效的双精度值 - 例如：

Private Function ToDouble(ByVal Value As String) As Double
    On Error GoTo ErrHandler
    ToDouble = CDbl(Value)
CleanExit:
    Exit Function
ErrHandler:
    Debug.Print "Value '" & Value & "' could not be converted and will be treated as 0"
    ToDouble = 0
    Resume CleanExit
End Function

现在您可以大大简化您的代码（Tim's advice 更是如此）：

total = total + ToDouble(Trading_calculator1.txt_currency1.Value)
...

旁注，如果Trading_calculator1 是一个用户表单，并且该代码位于该表单的代码隐藏模块中，您可以通过将表单称为Me 来避免将来的麻烦，如下所示：

total = total + ToDouble(Me.txt_currency1.Value)
...

确保函数为除数返回一个非零值，否则您现在将收到 除以零 错误。