simple question for a vb6 guy

[project2501]

I have some code that I am having issues with.. The code blows up if the registry value doesnt exist. This is what I am trying to check for but I get an run time error because it doesnt exist.

I just want to return a value of "not" if the registry value does not exist. Can someone help me out?

Thanks! Below is the code I have (as a function). This should be pretty simple but vb6 syntax is a challenge for me.

Function checkinstalled()
Dim WSH, result, theval
Set WshShell = CreateObject("WScript.Shell")

theval = WshShell.RegRead("HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\InstallRoot")
If theval <> "" Then
result = "installed"
Else
result = "not"
End If

End Function

[DigiRev]

You could use...

Function checkinstalled()
    On Error Goto ErrorHandler
 
        Dim WSH, result, theval
        Set WshShell = CreateObject("WScript.Shell")
      
          theval = WshShell.RegRead("HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\InstallRoot")
            If theval <> "" Then
                result = "installed"
            Else
                result = "not"
            End If
 
Exit Function
 
ErrorHandler:
 
          
    End Function

[project2501]

You could use...

Function checkinstalled()
    On Error Goto ErrorHandler
 
        Dim WSH, result, theval
        Set WshShell = CreateObject("WScript.Shell")
      
          theval = WshShell.RegRead("HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\InstallRoot")
            If theval <> "" Then
                result = "installed"
            Else
                result = "not"
            End If
 
Exit Function
 
ErrorHandler:
 
          
    End Function

yes I tried that but it returns a null value. I also tried to do this: but it still returns null value:

ErrorHandler: result = "not"

how could I do the above properly? Thanks again!

[Comintern]

I wouldn't use the WshShell for this -- I'd use API calls instead. Try this:

Const HKEY_LOCAL_MACHINE = &H80000002
Const STANDARD_RIGHTS_ALL = &H1F0000
Const SYNCHRONIZE = &H100000
Const READ_CONTROL = &H20000
Const STANDARD_RIGHTS_READ = (READ_CONTROL)
Const STANDARD_RIGHTS_WRITE = (READ_CONTROL)
Const KEY_CREATE_LINK = &H20
Const KEY_CREATE_SUB_KEY = &H4
Const KEY_ENUMERATE_SUB_KEYS = &H8
Const KEY_NOTIFY = &H10
Const KEY_QUERY_VALUE = &H1
Const KEY_SET_VALUE = &H2
Const KEY_READ = ((STANDARD_RIGHTS_READ Or KEY_QUERY_VALUE Or KEY_ENUMERATE_SUB_KEYS Or KEY_NOTIFY) And (Not SYNCHRONIZE))
Const KEY_WRITE = ((STANDARD_RIGHTS_WRITE Or KEY_SET_VALUE Or KEY_CREATE_SUB_KEY) And (Not SYNCHRONIZE))
Const KEY_EXECUTE = (KEY_READ)
Const KEY_ALL_ACCESS = ((STANDARD_RIGHTS_ALL Or KEY_QUERY_VALUE Or KEY_SET_VALUE Or KEY_CREATE_SUB_KEY Or KEY_ENUMERATE_SUB_KEYS Or KEY_NOTIFY Or KEY_CREATE_LINK) And (Not SYNCHRONIZE))
 
Private Declare Function RegCloseKey Lib "advapi32.dll" (ByVal hKey As Long) As Long
Private Declare Function RegOpenKeyEx Lib "advapi32.dll" Alias "RegOpenKeyExA" (ByVal hKey As Long, ByVal lpSubKey As String, ByVal Reserved As Long, ByVal samDesired As Long, phklKey As Long) As Long
 
Private Sub Example()
 
    Debug.Print KeyExists("SOFTWARE\Microsoft\.NETFramework\InstallRoot")
 
End Sub
 
Private Function KeyExists(sKey As String) As Boolean
 
    Dim lKey As Long
 
    Call RegOpenKeyEx(HKEY_LOCAL_MACHINE, sKey, 0, KEY_ALL_ACCESS, lKey)
    If lKey Then
        KeyExists = True
        Call RegCloseKey(lKey)
    End If
 
End Function

[project2501]

nice.. I think this is more along the lines of something I am looking for. I am not near the dev machine right now but will check it out tonight. I appreciate the help guys!

[Pradeep1210]

yes I tried that but it returns a null value. I also tried to do this: but it still returns null value:

ErrorHandler: result = "not"

how could I do the above properly? Thanks again!

In VB6, you return a value by a variable same as function name.

So instead of "result" everywhere in the code, you need to use "checkinstalled"

e.g.

checkinstalled = "installed"        '' not result = "installed"

Pradeep

[project2501]

huh... I was not aware of that. I suppose it makes sense though. I guess I never though about it since .NET you have a:

return (object)

[project2501]

I am still having issues. Using this code: Not matter what it always errors out:

Function checkinstalled()
On Error GoTo ErrorHandler

Dim WSH, result, theval
Set WshShell = CreateObject("WScript.Shell")

theval = WshShell.RegRead("HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\InstallRoot")
If theval <> "" Then
checkinstalled = "installed"
Else
checkinstalled = "not"
End If


ErrorHandler:
checkinstalled = "not"

End Function

Using this code It always returns "installed" (True) ... what am I doing wrong?

Const HKEY_LOCAL_MACHINE = &H80000002
Const STANDARD_RIGHTS_ALL = &H1F0000
Const SYNCHRONIZE = &H100000
Const READ_CONTROL = &H20000
Const STANDARD_RIGHTS_READ = (READ_CONTROL)
Const STANDARD_RIGHTS_WRITE = (READ_CONTROL)
Const KEY_CREATE_LINK = &H20
Const KEY_CREATE_SUB_KEY = &H4
Const KEY_ENUMERATE_SUB_KEYS = &H8
Const KEY_NOTIFY = &H10
Const KEY_QUERY_VALUE = &H1
Const KEY_SET_VALUE = &H2
Const KEY_READ = ((STANDARD_RIGHTS_READ Or KEY_QUERY_VALUE Or KEY_ENUMERATE_SUB_KEYS Or KEY_NOTIFY) And (Not SYNCHRONIZE))
Const KEY_WRITE = ((STANDARD_RIGHTS_WRITE Or KEY_SET_VALUE Or KEY_CREATE_SUB_KEY) And (Not SYNCHRONIZE))
Const KEY_EXECUTE = (KEY_READ)
Const KEY_ALL_ACCESS = ((STANDARD_RIGHTS_ALL Or KEY_QUERY_VALUE Or KEY_SET_VALUE Or KEY_CREATE_SUB_KEY Or KEY_ENUMERATE_SUB_KEYS Or KEY_NOTIFY Or KEY_CREATE_LINK) And (Not SYNCHRONIZE))

Private Declare Function RegCloseKey Lib "advapi32.dll" (ByVal hKey As Long) As Long
Private Declare Function RegOpenKeyEx Lib "advapi32.dll" Alias "RegOpenKeyExA" (ByVal hKey As Long, ByVal lpSubKey As String, ByVal Reserved As Long, ByVal samDesired As Long, phklKey As Long) As Long

Private Sub Example()

Debug.Print KeyExists("SOFTWARE\Microsoft\.NETFramework\InstallRoot")

End Sub

Private Function KeyExists(sKey As String) As Boolean

Dim lKey As Long

Call RegOpenKeyEx(HKEY_LOCAL_MACHINE, sKey, 0, KEY_ALL_ACCESS, lKey)
If lKey Then
KeyExists = True
Call RegCloseKey(lKey)
End If

End Function

[project2501]

WOOPS.. I mean this always returns FALSE

Using this code It always returns "installed" (True) ... what am I doing wrong?

Const HKEY_LOCAL_MACHINE = &H80000002
Const STANDARD_RIGHTS_ALL = &H1F0000
Const SYNCHRONIZE = &H100000
Const READ_CONTROL = &H20000
Const STANDARD_RIGHTS_READ = (READ_CONTROL)
Const STANDARD_RIGHTS_WRITE = (READ_CONTROL)
Const KEY_CREATE_LINK = &H20
Const KEY_CREATE_SUB_KEY = &H4
Const KEY_ENUMERATE_SUB_KEYS = &H8
Const KEY_NOTIFY = &H10
Const KEY_QUERY_VALUE = &H1
Const KEY_SET_VALUE = &H2
Const KEY_READ = ((STANDARD_RIGHTS_READ Or KEY_QUERY_VALUE Or KEY_ENUMERATE_SUB_KEYS Or KEY_NOTIFY) And (Not SYNCHRONIZE))
Const KEY_WRITE = ((STANDARD_RIGHTS_WRITE Or KEY_SET_VALUE Or KEY_CREATE_SUB_KEY) And (Not SYNCHRONIZE))
Const KEY_EXECUTE = (KEY_READ)
Const KEY_ALL_ACCESS = ((STANDARD_RIGHTS_ALL Or KEY_QUERY_VALUE Or KEY_SET_VALUE Or KEY_CREATE_SUB_KEY Or KEY_ENUMERATE_SUB_KEYS Or KEY_NOTIFY Or KEY_CREATE_LINK) And (Not SYNCHRONIZE))

Private Declare Function RegCloseKey Lib "advapi32.dll" (ByVal hKey As Long) As Long
Private Declare Function RegOpenKeyEx Lib "advapi32.dll" Alias "RegOpenKeyExA" (ByVal hKey As Long, ByVal lpSubKey As String, ByVal Reserved As Long, ByVal samDesired As Long, phklKey As Long) As Long

Private Sub Example()

Debug.Print KeyExists("SOFTWARE\Microsoft\.NETFramework\InstallRoot")

End Sub

Private Function KeyExists(sKey As String) As Boolean

Dim lKey As Long

Call RegOpenKeyEx(HKEY_LOCAL_MACHINE, sKey, 0, KEY_ALL_ACCESS, lKey)
If lKey Then
KeyExists = True
Call RegCloseKey(lKey)
End If

End Function

[Pradeep1210]

That's because you forgot to put an Exit Sub.

Function checkinstalled()
On Error GoTo ErrorHandler
 
Dim WSH, result, theval
Set WshShell = CreateObject("WScript.Shell")
 
theval = WshShell.RegRead("HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\InstallRoot")
If theval <> "" Then
checkinstalled = "installed"
Else
checkinstalled = "not"
End If
 
[B]Exit Function[/B]
ErrorHandler:
checkinstalled = "not"
 
End Function

Edit: Corrected

Pradeep

[project2501]

why would the code proceed through the ErrorHandler: code if there was no error?

[Pradeep1210]

why would the code proceed through the ErrorHandler: code if there was no error?

b'coz u didn't tell it to stop before that

[litlewiki]

ErrorHandlers a label that you specified.The code will follow its normal course untill you put an end to it!

[techgnome]

And since it's a Function is should be Exit Function.... not Exit Sub (shame on you Pradeep1210!)

-tg

[Pradeep1210]

And since it's a Function is should be Exit Function.... not Exit Sub (shame on you Pradeep1210!)

-tg

Thanks

(It was such a small declaration that I took it for a Sub. )
I always specify the return type of my functions even if they return variants and much used to see that syntax.


project2501:
Besides changing "Exit Sub" to Exit Function, You should modify the declaration to include return type.

Function checkinstalled()[B] as String[/B]

Pradeep