Variable 'xxx' is used before it has been assigned a value

Hi all

I am using the following VB6 code and I get this error Variable 'osv' is used before it has been assigned a value in VB2010.
I want to use this code/method for getting the version, I just want to fix this code:

Code:

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Public Class Form1

  Private Declare Function GetVersionEx Lib "kernel32" Alias "GetVersionExA" _
    (lpVersionInformation As OSVERSIONINFO) As Long

  Private Structure OSVERSIONINFO
      Dim OSVSize As Integer
      Dim dwVerMajor As Integer
      Dim dwVerMinor As Integer
      Dim dwBuildNumber As Integer
      Dim PlatformID As Integer
      Dim szCSDVersion As String
  End Structure

  Private Const VER_PLATFORM_WIN32s = 0
  Private Const VER_PLATFORM_WIN32_WINDOWS = 1
  Private Const VER_PLATFORM_WIN32_NT = 2

  ' Returns the version of Windows that the user is running
  Public Function GetWindowsVersion() As String
      Dim osv As OSVERSIONINFO

      osv = 0
      osv.OSVSize = Len(OSVERSIONINFO)

      If GetVersionEx(osv) = 1 Then
        Select Case osv.PlatformID
            Case VER_PLATFORM_WIN32s
              GetWindowsVersion = "Win32s on Windows 3.1"
            Case VER_PLATFORM_WIN32_NT
              GetWindowsVersion = "Windows NT"

              Select Case osv.dwVerMajor
                  Case 3
                    GetWindowsVersion = "Windows NT 3.5"
                  Case 4
                    GetWindowsVersion = "Windows NT 4.0"
                  Case 5
                    Select Case osv.dwVerMinor
                        Case 0
                          GetWindowsVersion = "Windows 2000"
                        Case 1
                          GetWindowsVersion = "Windows XP"
                        Case 2
                          GetWindowsVersion = "Windows Server 2003"
                    End Select
                  Case 6
                    Select Case osv.dwVerMinor
                        Case 0
                          GetWindowsVersion = "Windows Vista/Server 2008"
                        Case 1
                          GetWindowsVersion = "Windows 7/Server 2008 R2"
                    End Select
              End Select

            Case VER_PLATFORM_WIN32_WINDOWS
              Select Case osv.dwVerMinor
                  Case 0
                    GetWindowsVersion = "Windows 95"
                  Case 90
                    GetWindowsVersion = "Windows Me"
                  Case Else
                    GetWindowsVersion = "Windows 98"
              End Select
        End Select
      Else
        GetWindowsVersion = "Unable to identify your version of Windows."
      End If
  End Function

  Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
  ....
  call GetWindowsVersion to show win version
  ....
  End Sub
End Class

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Why not use managed code, examples

Code:

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Function IsWinVista() As Boolean
    Dim osInfo As System.OperatingSystem = System.Environment.OSVersion
    Return (osInfo.Platform = PlatformID.Win32NT AndAlso osInfo.Version.Major = 6)
End Function
Function IsWinXP() As Boolean
    Dim osInfo As System.OperatingSystem = System.Environment.OSVersion
    Return (osInfo.Platform = PlatformID.Win32NT AndAlso osInfo.Version.Major = 5 AndAlso osInfo.Version.Minor >= 1)
End Function

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Quote:

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Originally Posted by remusrigo

Hi all

I am using the following VB6 code and I get this error Variable 'osv' is used before it has been assigned a value in VB2010.
I want to use this code/method for getting the version, I just want to fix this code:

Code:

---

Public Class Form1

  Private Declare Function GetVersionEx Lib "kernel32" Alias "GetVersionExA" _
    (lpVersionInformation As OSVERSIONINFO) As Long

  Private Structure OSVERSIONINFO
      Dim OSVSize As Integer
      Dim dwVerMajor As Integer
      Dim dwVerMinor As Integer
      Dim dwBuildNumber As Integer
      Dim PlatformID As Integer
      Dim szCSDVersion As String
  End Structure

  Private Const VER_PLATFORM_WIN32s = 0
  Private Const VER_PLATFORM_WIN32_WINDOWS = 1
  Private Const VER_PLATFORM_WIN32_NT = 2

  ' Returns the version of Windows that the user is running
  Public Function GetWindowsVersion() As String
      Dim osv As OSVERSIONINFO

      osv = 0
      osv.OSVSize = Len(OSVERSIONINFO)

      If GetVersionEx(osv) = 1 Then
        Select Case osv.PlatformID
            Case VER_PLATFORM_WIN32s
              GetWindowsVersion = "Win32s on Windows 3.1"
            Case VER_PLATFORM_WIN32_NT
              GetWindowsVersion = "Windows NT"

              Select Case osv.dwVerMajor
                  Case 3
                    GetWindowsVersion = "Windows NT 3.5"
                  Case 4
                    GetWindowsVersion = "Windows NT 4.0"
                  Case 5
                    Select Case osv.dwVerMinor
                        Case 0
                          GetWindowsVersion = "Windows 2000"
                        Case 1
                          GetWindowsVersion = "Windows XP"
                        Case 2
                          GetWindowsVersion = "Windows Server 2003"
                    End Select
                  Case 6
                    Select Case osv.dwVerMinor
                        Case 0
                          GetWindowsVersion = "Windows Vista/Server 2008"
                        Case 1
                          GetWindowsVersion = "Windows 7/Server 2008 R2"
                    End Select
              End Select

            Case VER_PLATFORM_WIN32_WINDOWS
              Select Case osv.dwVerMinor
                  Case 0
                    GetWindowsVersion = "Windows 95"
                  Case 90
                    GetWindowsVersion = "Windows Me"
                  Case Else
                    GetWindowsVersion = "Windows 98"
              End Select
        End Select
      Else
        GetWindowsVersion = "Unable to identify your version of Windows."
      End If
  End Function

  Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
  ....
  call GetWindowsVersion to show win version
  ....
  End Sub
End Class

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Set Option Strict On and note more issues than the one you got.