FileNotFoundException for mscorlib.XmlSerializers.DLL, which doesn't exist

Question

I'm using an XmlSerializer to deserialize a particular type in mscorelib.dll

XmlSerializer ser = new XmlSerializer( typeof( [.Net type in System] ) );
return ([.Net type in System]) ser.Deserialize( new StringReader( xmlValue ) );

This throws a caught FileNotFoundException when the assembly is loaded:

"Could not load file or assembly 'mscorlib.XmlSerializers, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' or one of its dependencies. The system cannot find the file specified."

FusionLog:

=== Pre-bind state information ===
LOG: User = ###
LOG: DisplayName = mscorlib.XmlSerializers, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089, processorArchitecture=x86
 (Fully-specified)
LOG: Appbase = file:///C:/localdir
LOG: Initial PrivatePath = NULL
Calling assembly : System.Xml, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089.
===
LOG: This bind starts in default load context.
LOG: Using application configuration file: C:\localdir\bin\Debug\appname.vshost.exe.Config
LOG: Using machine configuration file from c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\config\machine.config.
LOG: Post-policy reference: mscorlib.XmlSerializers, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089, processorArchitecture=x86
LOG: Attempting download of new URL file:///C:/localdir/bin/Debug/mscorlib.XmlSerializers.DLL.
LOG: Attempting download of new URL file:///C:/localdir/bin/Debug/mscorlib.XmlSerializers/mscorlib.XmlSerializers.DLL.
LOG: Attempting download of new URL file:///C:/localdir/bin/Debug/mscorlib.XmlSerializers.EXE.
LOG: Attempting download of new URL file:///C:/localdir/bin/Debug/mscorlib.XmlSerializers/mscorlib.XmlSerializers.EXE.

As far as I know there is no mscorlib.XmlSerializers.DLL, I think the DLL name has bee auto generated by .Net looking for the serializer.

You have the option of creating a myApplication.XmlSerializers.DLL when compiling to optimise serializations, so I assume this is part of the framework's checking for it.

The problem is that this appears to be causing a delay in loading the application - it seems to hang for a few seconds at this point.

Any ideas how to avoid this or speed it up?

Answer 1

The delay is because, having been unable to find the custom serializer dll, the system is building the equivalent code (which is very time-consuming) on the fly.

The way to avoid the delay is to have the system build the DLL, and make sure it's available to the .EXE - have you tried this?