AppDomain / Assembly Bug or what's wrong?

[Cider123]

The following is a basic example of how this system works:

C:\MyApp\Application1.exe
C:\MyApp\MyMonitor.exe

In SQL Server, we keep an EXE (Application1.exe) file stored as
binary.

I read this out of SQL Server into a byte[] array (through
MyMonitor.exe) and then pass to a function for Version.

Here's the kicker.. As soon as the function loads the binary image
retreieved from SQL Server, it *locks* the local "Application1.exe"
running out of the same directory.

I'm puzzled by 2 things:

1) why does the local Application1.exe get locked when I'm loading a
secondary app domain with a byte array from SQL?

2) Let's say technically it's a bug, and it's using the
"Application1.exe" from the local folder--then why is it not released
when I unload the secondary application domain?

When I terminate "MyMonitor.exe" I can then copy a newer build over
the existing "Application1.exe" file. If I comment out the section
that deals with loading the Byte[] array, I can copy a newer build
over the existing file. However, my design is flawed in some way or
this is a bug.

Any help appreciated.
Here's the GetAssemblyVersion Function:

pprivate string GetAssemblyVersion(byte[] inBytes)
{
string strVersion = "";

try
{
AppDomain secDomain = AppDomain.CreateDomain("SecondaryDomain",
null, null);

int iStart = 0;
int iStop = 0;

secDomain.Load(inBytes);

Assembly[] oList = secDomain.GetAssemblies();
iStart = oList[0].FullName.IndexOf("Version") + 8;
iStop = oList[0].FullName.IndexOf(",", iStart);

strVersion = oList[0].FullName.Substring(iStart, (iStop - iStart));

AppDomain.Unload(secDomain);

}
catch (Exception e1)
{
MessageBox.Show("Error encountered Reading Assembly Info: " +
e1.ToString());
}

return strVersion;
}

[David Levine]

You have to load the assembly from within the context of the 2nd appdomain -
in your snippet you are loading it while executing in the default appdomain.
You need to create a class derived from MarshalByRefObj and call a method in
it that will actually load the assembly. Do not pass a reference back to the
default appdomain because that will force it to load the assembly in that
appdomain.

This link explains this and has sample code on how to do it.

http://www.gotdotnet.com/team/clr/AppdomainFAQ.aspx

Another option is write code that will examine the bytes that make up the PE
file header info and parse it yourself.

"Cider123" <ci******@hotmail.com> wrote in message
news:55**************************@posting.google.c om...

The following is a basic example of how this system works:

C:\MyApp\Application1.exe
C:\MyApp\MyMonitor.exe

In SQL Server, we keep an EXE (Application1.exe) file stored as
binary.

I read this out of SQL Server into a byte[] array (through
MyMonitor.exe) and then pass to a function for Version.

Here's the kicker.. As soon as the function loads the binary image
retreieved from SQL Server, it *locks* the local "Application1.exe"
running out of the same directory.

I'm puzzled by 2 things:

1) why does the local Application1.exe get locked when I'm loading a
secondary app domain with a byte array from SQL?

2) Let's say technically it's a bug, and it's using the
"Application1.exe" from the local folder--then why is it not released
when I unload the secondary application domain?

When I terminate "MyMonitor.exe" I can then copy a newer build over
the existing "Application1.exe" file. If I comment out the section
that deals with loading the Byte[] array, I can copy a newer build
over the existing file. However, my design is flawed in some way or
this is a bug.

Any help appreciated.
Here's the GetAssemblyVersion Function:

pprivate string GetAssemblyVersion(byte[] inBytes)
{
string strVersion = "";

try
{
AppDomain secDomain = AppDomain.CreateDomain("SecondaryDomain",
null, null);

int iStart = 0;
int iStop = 0;

secDomain.Load(inBytes);

Assembly[] oList = secDomain.GetAssemblies();
iStart = oList[0].FullName.IndexOf("Version") + 8;
iStop = oList[0].FullName.IndexOf(",", iStart);

strVersion = oList[0].FullName.Substring(iStart, (iStop - iStart));

AppDomain.Unload(secDomain);

}
catch (Exception e1)
{
MessageBox.Show("Error encountered Reading Assembly Info: " +
e1.ToString());
}

return strVersion;
}