Question

我遇到的问题是我在某些XP机器上运行的VB.NET中编写的工具。该工具运行正常，并且在具有.NET 4.0.30319.1022的Windows 7和XP计算机上正常运行。

我注意到我遇到麻烦的XP机器是那些没有.NET 4的机器，所以我去安装.NET 4，它安装了.NET 4.0.30319.1。< / p>

这是错误：

以下是第86行的代码（86代表For Each）：

'_BIOSVer
Dim bios_query As String = "SELECT * FROM " & "Win32_BIOS"
Dim bios_searcher As New ManagementObjectSearcher(bios_query)
For Each info As ManagementObject In bios_searcher.Get()
    _BIOSVer = info.Properties("BIOSVersion").Value.ToString()
Next info

我正在运行.NET 4 Framework的Windows更新，看看是否能解决这个问题，但我想知道你们是否了解发生了什么，或者我的代码是否错误。

更新刚刚完成，重新启动。它运行.NET 4.0.30319.1022但仍然抛出该错误。那么一定是我的代码。

Answer 1

BIOS Version返回一个字符串数组（有关详细信息，请查看this link）。

尝试阅读这样的数据

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim BIOSSearcher As New ManagementObjectSearcher("SELECT BIOSVersion FROM Win32_BIOS")
    Dim BIOSVersionInfo() As String = BIOSSearcher.Get(0).Properties("BIOSVersion").Value
    Dim BIOSVersion As String = ""

    If Not BIOSVersionInfo Is Nothing Then
        BIOSVersion = String.Join(vbCrLf, BIOSVersionInfo)
    End If

    MsgBox(BIOSVersion)
End Sub

Answer 2

有几个问题，但主要是BIOSVersion是一个字符串数组。您可以直接获取返回版本信息的Name（Caption和Description也是如此）。由于你是一件事，你不需要一个循环，但我把它留作模板：

Dim myver As String = ""
Using searcher As New ManagementObjectSearcher("Select Name From Win32_Bios")
    For Each mo As ManagementObject In searcher .Get

        ' EXAMPLE
         'DebugProperties(mo)

        ' no real need to Loop - just for illustration
        For Each pd As System.Management.PropertyData In mo.Properties

            ' if you do SELECT * and want to find something,
            ' compare Pd.Name to the target property 

            ' some things can be nothing.  Such as when a property does not
            ' exist on older systems, so always test:
            If pd.Value IsNot Nothing Then
                myver = pd.Value.ToString
                Exit For
            End If
        Next
    Next

End Using

Return myver

这是一个有用的WMI调试工具，用于显示所有属性名称和值（上面的代码调用了这个注释掉了）：

Private Shared Sub DebugProperties(mo As Management.ManagementObject)

    For Each pd As PropertyData In mo.Properties
        If pd.Value IsNot Nothing Then
            Console.WriteLine("{0} {1}", pd.Name,
                              If(pd.Value IsNot Nothing,
                                 pd.Value.ToString,
                                 "Nothing"))
        End If

    Next
End Sub

选择的XP机器上的InvalidCastException

2 个答案: