IsNumeric() 在数字上失败的任何原因？

发布于 2024-07-29 07:30:21 字数 221 浏览 6 评论 0 原文

我目前有这行代码，在过去的 6 个月里一直在工作：

If IsNumeric(txtProductID.Text) Then
   ...do stuff
Else
   Dim msg As String = "Error!"
End If

突然之间，无论在 txtProductID 中放入什么样的条目（包括纯数字），它都会失败！我有理由为此疯狂吗？

原文

I currently have this line of code which has been working for the past 6 months:

If IsNumeric(txtProductID.Text) Then
   ...do stuff
Else
   Dim msg As String = "Error!"
End If

All of the sudden, no matter what kind of entry is put in txtProductID (including plain numbers), it fails! Is there reason for me to be going crazy over this?

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魔法唧唧 2024-08-05 07:30:22

在将字符串传递给函数之前尝试对字符串进行 Trim() 处理。此外，您可以尝试以下方法，而不是使用像 IsNumeric 这样的 VB 特定函数：

Dim input as Integer

If Integer.TryParse(txtProductID.Text, input) Then
    ....do stuff with input
Else
    Dim msg as String = "Error!"
End if

如果您的数字是十进制数，则 Double 上有相应的函数以及Single。

至于 IsNumeric 失败的具体原因，我无法告诉你。不过，我可以告诉您，我一直发现坚持使用与语言无关而不是特定于语言的 BCL 兼容函数很有帮助，例如 IsNumeric、Str 等

Try Trim()ing the string before passing it into the function. In addition, rather than using a VB-specific function like IsNumeric, you might try an approach like this:

Dim input as Integer

If Integer.TryParse(txtProductID.Text, input) Then
    ....do stuff with input
Else
    Dim msg as String = "Error!"
End if

If your number is a decimal number, there are corresponding functions on Double and Single as well.

As to the particular reason that IsNumeric is failing, I couldn't tell you. I can tell you, though, that I've always found it helpful to stick to BCL-compliant functions that are language-agnostic rather than language-specific, like IsNumeric, Str, etc.