Question

I am just learning Blend/Silverlight/VS2010/.net/etc. I have a simple project that resides on a network drive. When I tell VS2010 to rebuild the project, I get the following error message:

------ Rebuild All started: Project: MySilverlightApplication, Configuration: Debug Any CPU ------
  MySilverlightApplication -> H:\PRJ\VisualStudio\ExpressionBlend\Unleashed\MySilverLightApplication\MySilverlightApplication\Bin\Debug\MySilverlightApplication.dll

C:\Program Files\MSBuild\Microsoft\Silverlight\v4.0\Microsoft.Silverlight.Common.targets(214,9):
 error : Could not load the assembly 
         file:///H:\PRJ\VisualStudio\ExpressionBlend\Unleashed\MySilverLightApplication\MySilverlightApplication\obj\Debug\MySilverlightApplication.dll.
         This assembly may have been downloaded from the Web.  If an assembly has been downloaded from the Web,
         it is flagged by Windows as being a Web file, even if it resides on the local computer.
         This may prevent it from being used in your project. You can change this designation by changing the file properties.
         Only unblock assemblies that you trust. See http://go.microsoft.com/fwlink/?LinkId=179545 for more information.
========== Rebuild All: 0 succeeded, 1 failed, 0 skipped ==========

The project was not downloaded from the Web (I created it using Blend.) After doing some searching, I guessed the problem may be due to .net security settings. I issued the following command:

C:\Program Files\Microsoft Visual Studio 10.0\VC>caspol -m -ag 1.3 -url "file://\\p4dc\h$\*" FullTrust

in the hope that would solve the problem. p4dc is the name of the server machine, h$ is the administrative share for the h: drive on the server which in turn is mapped to the drive letter “H” on the local machine (\\p4dc\h$ is mapped to H in the local machine).

That did not solve the problem. I don’t know if my caspol command is correct (I wasn’t planning on learning caspol on the fly), it just seemed like a reasonable thing to try. The problem goes away when I make a copy of the entire project on the local C drive but, that “solution” is rather undesirable.

At this point, I don’t really know what else to try to solve the problem without moving the project to a local drive.

Any help leading to a solution is much appreciated.

John.

Answer 1

The error message displayed by VS2010 would lead anyone to believe the issue is with trust and security and it is BUT, no amount of allowing full trust on the network drive will solve the problem.

What lead to the solution was first to port the project to VS2008 to find out if it would encounter the same problem. VS2008 was perfectly happy to run the project without complaint.

Then I converted the VS2008 project (which was working) to VS2010. VS2010 refused to build the project but this time the error message was different, referring to “remote assemblies” and to a link on MSDN, which led to the solution.

The real problem is that VS2010 considers an assembly on a network drive a “remote assembly” (the same as if the assembly were being loaded from a web site.) Caspol was not able to solve that problem (it seems it should have but, it may be my fault, I am not well versed in using Caspol).

To end this long story, the link provided in the error message is:

http://msdn.microsoft.com/en-us/library/dd409252(VS.100).aspx

after following the instructions in that link to edit “machine.config”, I changed <runtime/> to:

<runtime>
  <loadFromRemoteSources enabled="true"/>
</runtime>

the project built successfully and ran without a hitch.

Thank you to Alison and CodeNaked for their efforts to help,

John.

PS: it would have been rather nice if VS2010 had displayed the “better” error message initially. Instead, I had to port the VS2010 non working project to VS2008 where it worked and that one to VS2010 where I got the better error message that led to the solution.