System.AccessViolationException exception in C# and shell32.dll

Question

i write a snippet code that deletes a specified directory in SHFileOperation method.

The SHFileOperation class from a pinvoke.net

the flowing is my test code:

 var interop = new InteropSHFileOperation();
 interop.wFunc = InteropSHFileOperation.FO_Func.FO_DELETE;
 interop.pFrom = path;
 interop.fFlags.FOF_SILENT = true;
 interop.fFlags.FOF_NOERRORUI = true;
 interop.fFlags.FOF_NOCONFIRMATION = true;
 return interop.Execute();

the above code can worked in my computer(win7,32-bit,.net 4.0),

but when running above code to my other computer(win 2008,64-bit,.net 4.0),i get the flowing error(from windows event viewer):

Description: The process was terminated due to an unhandled exception.
Exception Info: System.AccessViolationException
Stack:
   at Shopbots.IO.InteropSHFileOperation.SHFileOperation(SHFILEOPSTRUCT ByRef)
   at Shopbots.IO.InteropSHFileOperation.SHFileOperation(SHFILEOPSTRUCT ByRef)
   at Shopbots.IO.InteropSHFileOperation.Execute()

and from windows exceton dialog

event name : APPCRASH
Fault Module Name:  shell32.dll
Fault Module Version:   6.0.6002.18646
Fault Module Timestamp: 4fd23d65
Exception Code: c0000005

[update 2]

according "Don't declare a value for the Pack size. If you omit it, the correct value is used when marshaling and a single SHFILEOPSTRUCT can be used for both 32-bit and 64-bit operation." from a other article:http://www.pinvoke.net/default.aspx/Structures/SHFILEOPSTRUCT.html:

change a SHFILEOPSTRUCT declare that work 32-bit and 64-bit windows operator system(because the InteropSHFileOperation class from pinvoke site that declare a SHFILEOPSTRUCT structure for 32-bit operator system)

[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Unicode)]
struct SHFILEOPSTRUCT
{
  ....
}

Did you read the comments about the string needing to be double null terminated? pinvoke.net/default.aspx/shell32.shfileoperation — ta.speot.is
– ta.speot.is, Commented Jul 13, 2013 at 5:45
yes,i have read.i just noticed this may be the operating system version 32 and 64 issues.i read again and notice about this :The SHFILEOPSTRUCT StructLayout attribute needs a Pack=2 (win32 - see this in the example) and Pack=8 (win64) parameter. Without it, it does not work. Of course both cannot be set for the same struct, so 2 structs are needed. — zhengchun
– zhengchun, Commented Jul 13, 2013 at 5:56
Don't pinvoke this, it is already wrapped by the .NET framework. Use FileSystem.DeleteFile() instead. — Hans Passant
– Hans Passant, Commented Jul 14, 2013 at 19:34
It's a standard Win32 struct. It's aligned. Remove Pack from your declarations. — David Heffernan
– David Heffernan, Commented Jul 15, 2013 at 7:12

David Heffernan · Accepted Answer · 2013-07-15 10:41:51Z

1

The most common failure mode for SHFileOperation is that the paths need to be double null-terminated. I suspect that you have forgotten to do that and if you do so an access violation is one possible outcome.

As for packing of the struct, it's a standard Win32 struct. It's not packed, it is aligned. Remove the Pack parameter from the StructLayout attribute.

I cannot understand why you would not call FileSystem.DeleteDirectory.

edited Jul 15, 2013 at 10:41

answered Jul 15, 2013 at 7:15

David Heffernan

616k46 gold badges1.1k silver badges1.5k bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

System.AccessViolationException exception in C# and shell32.dll

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related