将字符串转换为Double - VB
将字符串转换为Double - VB
提问于 2009-07-23 14:49:21
在VB中有没有一种有效的方法来检查字符串是否可以转换为双精度？
我目前正在尝试将字符串转换为双精度值，然后查看它是否会抛出异常。但这似乎减慢了我的应用程序。
Try
' if number then format it.
current = CDbl(x)
current = Math.Round(current, d)
Return current
Catch ex As System.InvalidCastException
' item is not a number, do not format... leave as a string
Return x
End Try回答 4
Stack Overflow用户
回答已采纳
发布于 2009-07-23 14:53:22
如果您使用的是.NET 1.1/2.0/3.0/3.5/4.0/4.5，请尝试查看Double.TryParse()
Stack Overflow用户
发布于 2009-07-23 15:10:12
Dim text As String = "123.45"
Dim value As Double
If Double.TryParse(text, value) Then
' text is convertible to Double, and value contains the Double value now
Else
' Cannot convert text to Double
End IfStack Overflow用户
发布于 2015-01-13 22:59:57
国际版本：
Public Shared Function GetDouble(ByVal doublestring As String) As Double
Dim retval As Double
Dim sep As String = CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator
Double.TryParse(Replace(Replace(doublestring, ".", sep), ",", sep), retval)
Return retval
End Function
' NULLABLE VERSION:
Public Shared Function GetDoubleNullable(ByVal doublestring As String) As Double?
Dim retval As Double
Dim sep As String = CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator
If Double.TryParse(Replace(Replace(doublestring, ".", sep), ",", sep), retval) Then
Return retval
Else
Return Nothing
End If
End Function结果：
' HUNGARIAN REGIONAL SETTINGS (NumberDecimalSeparator: ,)
' Clean Double.TryParse
' -------------------------------------------------
Double.TryParse("1.12", d1) ' Type: DOUBLE Value: d1 = 0.0
Double.TryParse("1,12", d2) ' Type: DOUBLE Value: d2 = 1.12
Double.TryParse("abcd", d3) ' Type: DOUBLE Value: d3 = 0.0
' GetDouble() method
' -------------------------------------------------
d1 = GetDouble("1.12") ' Type: DOUBLE Value: d1 = 1.12
d2 = GetDouble("1,12") ' Type: DOUBLE Value: d2 = 1.12
d3 = GetDouble("abcd") ' Type: DOUBLE Value: d3 = 0.0
' Nullable version - GetDoubleNullable() method
' -------------------------------------------------
d1n = GetDoubleNullable("1.12") ' Type: DOUBLE? Value: d1n = 1.12
d2n = GetDoubleNullable("1,12") ' Type: DOUBLE? Value: d2n = 1.12
d3n = GetDoubleNullable("abcd") ' Type: DOUBLE? Value: d3n = Nothing页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/1172306
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