将 TextBox.Value 转换为 Double 到 VBA (Excel 2013)
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Convert TextBox.Value to Double into VBA (Excel 2013)
提问by 4est
I have TextBox into my form, where user can input a value. In VBA I need to convert the value from string to double.
我的表单中有 TextBox，用户可以在其中输入一个值。在 VBA 中，我需要将值从字符串转换为双精度值。
I'm doing it like:
我这样做：
Private Sub UserForm_Initialize()
'....some code
Dim new_value As Double
new_value = CDbl(TextBox6.Value)
End sub
But I'm getting the error below:
但我收到以下错误：
回答by P??
CDblexpects already a number but if the textbox is empty then TextBox6.Valueis an empty string. CDblcan't cast an empty string into a double.
CDbl期望已经是一个数字，但如果文本框为空，TextBox6.Value则为空字符串。CDbl不能将空字符串转换为双精度。
You can validate if the textbox is a numeric value first to avoid this
您可以先验证文本框是否为数值以避免这种情况
If IsNumeric(TextBox6.Value) Then
new_value = CDbl(TextBox6.Value)
Else
new_value = 0
End If
Alternatively the Val()function might be an option for you.
或者，该Val()功能可能是您的一个选择。
new_value = Val(TextBox6.Value)
回答by Top-Master
In case the user is allowed to use other characters (for example, the $sign), then the below function could be useful:
如果允许用户使用其他字符（例如，$符号），则以下函数可能很有用：
'
' Skips all characters in the input string except
' the first negative-sign, digits, and the first dot
'
Function ParseNumber(ByVal s As String) As Double
ParseNumber = 0#
Dim char As String
Dim i As Integer
Dim digits$
Dim isNegative As Boolean
Dim isPastDot As Boolean
For i = 1 To Len(s)
char = Mid(s, i, 1)
If char >= "0" And char <= "9" Then
digits = digits + char
ElseIf char = "-" Then
If Len(digits) <= 0 Then
isNegative = True
End If
ElseIf char = "." Then
If Not isPastDot Then
isPastDot = True
digits = digits & "."
End If
End If
Next i
ParseNumber = CDbl(digits)
If isNegative Then
ParseNumber = 0 - ParseNumber
End If
End Function
