FileStream question

[Tim Kohler]

I'm trying to open a file for writing in a server process. I do not want any
other process to be able to write to the file while I have it open, but I do
want to allow other programs to read from it. Seems simple enough. I've done
this with CFile in MFC. I'm getting a problem trying to use the .NET
FileStream class. I can open the files with other applications (notepad) and
they open up in 'readonly' mode which is what I expect. Can any of you shed
light on why I'm getting a 'File is in use' IO exception with this:

try
{
String Nm = "c:\\testfile.txt";

//simulate the server opening the file for writing:
FileStream str = File.Open(Nm, FileMode.Append, FileAccess.Write,
FileShare.Read);

//simulate some other process opening the file for reading: (exception
thrown here)
FileStream sss = File.OpenRead(Nm);
}
catch (IOException e)
{
System.Console.WriteLine(e.Message);
}
thanks
Tim