Error: Success...

2009-10-01T20:11:00.000+02:00

Introduction

Just some days we rolled out another small tool for our clients which was in testing for nearly six months. Since we are a small company (with not so many clients) we always install complete new tools by ourselves on the client machines...just in case. We tried it, it worked, perfect.

It wasn't me!

It worked perfectly, until the client called us that it didn't work. But, we use the .NET Framework for our new programs and the client just sent us the stacktrace of the exception *cool*...I stared unbelieving at it:

System.ComponentModel.Win32Exception: The operation completed successfully

at System.Windows.Forms.Form.UpdateLayered()
at System.Windows.Forms.Form.OnHandleCreated(EventArgs e)
at System.Windows.Forms.Control.WmCreate(Message& m)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
at System.Windows.Forms.ContainerControl.WndProc(Message& m)
at System.Windows.Forms.Form.WmCreate(Message& m)
at System.Windows.Forms.Form.WndProc(Message& m)
at System.Windows.Forms.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32
msg, IntPtr wparam, IntPtr lparam)

"Okay, what's that?" It took me over half an hour to figure out that this was waaaaaay before my own code, and another half hour to figure out what that is...

Reflector is telling me...nothing...

If you break down the Stacktrace and follow it with Reflector you'll end up here:

Private Sub UpdateLayered()
If (((Me.formState.Item(Form.FormStateLayered) <> 0) AndAlso
MyBase.IsHandleCreated) AndAlso (Me.TopLevel AndAlso
OSFeature.Feature.IsPresent(OSFeature.LayeredWindows))) Then
Dim flag As Boolean
Dim transparencyKey As Color = Me.TransparencyKey
If transparencyKey.IsEmpty Then
flag = UnsafeNativeMethods.SetLayeredWindowAttributes(New
HandleRef(Me, MyBase.Handle), 0, Me.OpacityAsByte, 2)
ElseIf (Me.OpacityAsByte = &HFF) Then
flag = UnsafeNativeMethods.SetLayeredWindowAttributes(New
HandleRef(Me, MyBase.Handle), ColorTranslator.ToWin32(transparencyKey),
0, 1)
Else
flag = UnsafeNativeMethods.SetLayeredWindowAttributes(New
HandleRef(Me, MyBase.Handle), ColorTranslator.ToWin32(transparencyKey),
Me.OpacityAsByte, 3)
End If
If Not flag Then
Throw New Win32Exception
End If
End If
End Sub

I'm not using the transparency key so he has to fail at setting the window attributes...what the? You ever saw the .NET Framework failing to create a window? Nope, me neither...

Third-Party

The answer to this riddle popped to my mind that moment I thought about how the program was called...we have a main DOS-Application which we are slowly enhancing and replacing with .NET programs, some of our clients have figured out how to start this program in fullscreen...and I mean the command fullscreen option.

Conclusion

For some reason (which I most likely never understand) fails the framework to create the window out of this fullscreen mode, but is able to minimize the command prompt and show the stacktrace window...whatever...

.NET on a Network Share

2009-06-07T21:33:00.000+02:00

Some programs don't need to be installed, for some programs it's sufficient to start from a network share. Unfortunately, by default it's forbidden to start a .NET program from a network share...this behavior was changed with 3.5 SP1, but at least for 2.0 exists e pretty simple command to allow this behavior, which needs to be executed on the client machine.

%WINDIR%\Microsoft.NET\Framework\v2.0.50727\CasPol.exe -m -ag 1.2 -url file://yourserver/* FullTrust

Sites you should know

2008-08-11T20:14:00.000+02:00

There are two sites you should really know.

PInvoke:
PInvoke is an Wiki-like site which is a (nearly) complete documentation of the Win32 API. If you think about working with the API (which is sometimes pretty handy), then your first look should go to this site.

Connection Strings:
All kind of different Connection Strings to databases and files. Starts at common strings like MySQL and ends in less common data sources like an Excel file.

Bonsai Mind