VB6用注册表检测.Net Framework版本是否存在

在开发.Net程序之后就是发布，发布时就会有一个稍微令人有点头疼的问题，就是.Net2.0和4.0的问题，这里我用VB6写了个类，可以用来检测.Net2.0/3.5/4.0、系统位数判断和系统是否为XP，通过检测来决定是否安装.Net版本，或者运行不同的程序。

Public Function isdotNET40() As Boolean
    On Error GoTo err
    Dim NET As Object
    Set NET = CreateObject("wscript.shell")
    Dim a As String
    a = NET.regread("HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4.0\Client\Version")
    isdotNET40 = True
    Exit Function
err:
    isdotNET40 = False
End Function
Public Function isdotNET35() As Boolean
    On Error GoTo err
    Dim NET As Object
    Set NET = CreateObject("wscript.shell")
    Dim a As String
    a = NET.regread("HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v3.5\Version")
    isdotNET35 = True
    Exit Function
err:
    isdotNET35 = False
End Function
Public Function isdotNET20() As Boolean
    On Error GoTo err
    Dim NET As Object
    Set NET = CreateObject("wscript.shell")
    Dim a As String
    a = NET.regread("HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v2.0.50727\Version")
    isdotNET20 = True
    Exit Function
err:
    isdotNET20 = False
End Function
Public Function isXP() As Boolean
    On Error GoTo err
    Dim reg As Object
    Set reg = CreateObject("wscript.shell")
    Dim datas As String
    datas = reg.regread("HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProductName")
    If InStr(1, datas, "XP") <> 0 Then isXP = True Else isXP = False
    Exit Function
err:
    isXP = True
End Function
Public Function is64bit() As Boolean
    If Dir(Environ("Windir") & "\SysWOW64", vbDirectory) <> "" Then
        is64bit = True
    Else
        is64bit = False
    End If
End Function

Dim SysNet As New SysNet
If SysNet.isdotNET40 Then
    Shell App.path & "\Net40安装程序.exe" , 1
Else
    Shell App.path & "\主程序.exe" , 1
End If