UnauthorizedAccessException

[zackiv31]

Here's my code:

string drive = "c";
TextReader tr = new StreamReader(String.Format(@"{0}:\boot.ini.zives",drive));
tr.WriteLine("test");
tr.Flush();
tr.Close();

I'm running it under Administrator mode (the account), but I'm getting an access denied, with an UnauthorizedAccessException. The file isn't read only, although It's a system file. Any ideas on how to write to the boot.ini file?

 

[phinoppix]

On which line did you say you're getting an exception?

Btw, you can't use a stream reader for write operations, hence a reader. use a stream writer.

 

[GeertVerhoeven]

Normally the above code will not compile since the TextReader class has no WriteLine method.

You should change your code like this by using StreamWriter and TextWriter:

string drive = "c";
TextWriter tw = new StreamWriter(String.Format(@"{0}:\boot.ini.zives", drive));
tw.WriteLine("test");
tw.Flush();
tw.Close();

Greetz,

Geert

Geert Verhoeven
Consultant @ Ausy Belgium

My Personal Blog

 

[zackiv31]

Oops, sorry that's just a typo, I've been coding all day...

I did use textWriter and Streamwriter, but it throws an error on the instantiation.

Any ideas now?

 

[zackiv31]

Here's a better written version of my problem, the first one is totally wrong:

string drive = "c";
TextWriter tw = new StreamWriter(String.Format(@"{0}:\BOOT.INI",drive));
tw.WriteLine("test");
tw.Flush();
tw.Close();

It has to do with the fact that I'm writing the BOOT.INI file of windows, since it's a system file I guess? But I'm running the program with administrator privileges, so it should work.

 

[zackiv31]

bump

 

[phinoppix]

Afaik, you cannot write on a file with S, H, or R attributes (System, Hidden, Read-only) and Boot.INI has all 3 set.

To edit it, you must remove first these 3 attributes using System.IO.FileInfo.Attributes, do your changes on the file, then put back the attributes again.

System.IO.FileInfo fi = new System.IO.FileInfo("c:\\boot.ini");
			// Remove Hidden attribute
			fi.Attributes ^= System.IO.FileAttributes.Hidden;
			// Set Hidden attribute
			fi.Attributes |= System.IO.FileAttributes.Hidden;

 

[zackiv31]

I solved this at about the same time as you.

I Get it's attributes first, store them temporarily, set the files attributes to Archive, do all my writing, and reset the original attributes.

My boot.ini wasn't read only, so I think it was the system or hidden value that made it impossible to write... do you know which one?