Ever tried porting a DDE app to Windows XP/2003 that you know worked under Windows NT/9x? It just won't communicate. Having found the problem twice and then forgotten again, here's the note on what is (normally) wrong:
The NetDDE services (Control Panel-Administrative Tools-Services) need to be started. Set startup type to automatic (they are disabled by default), and to avoid rebooting the first time, start them as well.
Wednesday, June 11, 2008
Wednesday, June 4, 2008
VB.NET: Shell32 code compiled on Vista does not run on XP/2003
This was a tricky one, and I had a hard time finding a working solution. I finally found the solution by reading comments in differnt forum. I had to mix it together myself - here's the finished soup:
Situation: I had a VB.NET code that was based on VBscript code from "Hey, scripting guy" to programmatically pin shortcuts from the desktop onto the start menu. This line of code created a bit of a headache:
Dim oShell As Shell32.Shell = New Shell32.Shell
Dim oFolder As Shell32.Folder = oShell.NameSpace(0) '0 refers to user desktop
Problem: The code compiled and ran on my Vista computer, but once I moved the .exe file to a Server 2003 computer, it threw a runtime exception stating: Unable to cast COM object of type 'Shell32.ShellClass' to interface type 'Shell32.IShellDispatch5 and then the usual garble (actually, the garble did reveal the line of code in question)
Cause: The Shell32 library comes in a new version in Vista compared to XP/2003 - or that is my conception of what I could find on the subject. The problem is that under XP/2003, the Shell32.ShellClass is not casted to Shell32.IShellDispatch5, but to its predecessor, Shell32.IShellDispatch4. Now I knew the difference, but it meant that the program needs to reference the right one.
Solution: I found the two first lines of code below buried in a comment in a forum - when they replace the first line of code above, voilla: It works on all platforms (the term 'all' referring to XP, Server 2003 and Vista):
Dim ShellAppType As Type = Type.GetTypeFromProgID("Shell.Application")
Dim oShell As Object = Activator.CreateInstance(ShellAppType)
Dim oFolder As Shell32.Folder = oShell.NameSpace(0) '0 refers to user desktop
Nerds like me may be simple to please - it certainly made my day!
Situation: I had a VB.NET code that was based on VBscript code from "Hey, scripting guy" to programmatically pin shortcuts from the desktop onto the start menu. This line of code created a bit of a headache:
Dim oShell As Shell32.Shell = New Shell32.Shell
Dim oFolder As Shell32.Folder = oShell.NameSpace(0) '0 refers to user desktop
Problem: The code compiled and ran on my Vista computer, but once I moved the .exe file to a Server 2003 computer, it threw a runtime exception stating: Unable to cast COM object of type 'Shell32.ShellClass' to interface type 'Shell32.IShellDispatch5 and then the usual garble (actually, the garble did reveal the line of code in question)
Cause: The Shell32 library comes in a new version in Vista compared to XP/2003 - or that is my conception of what I could find on the subject. The problem is that under XP/2003, the Shell32.ShellClass is not casted to Shell32.IShellDispatch5, but to its predecessor, Shell32.IShellDispatch4. Now I knew the difference, but it meant that the program needs to reference the right one.
Solution: I found the two first lines of code below buried in a comment in a forum - when they replace the first line of code above, voilla: It works on all platforms (the term 'all' referring to XP, Server 2003 and Vista):
Dim ShellAppType As Type = Type.GetTypeFromProgID("Shell.Application")
Dim oShell As Object = Activator.CreateInstance(ShellAppType)
Dim oFolder As Shell32.Folder = oShell.NameSpace(0) '0 refers to user desktop
Nerds like me may be simple to please - it certainly made my day!
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