Some DLLs require Full Trust because they contain unmanaged code, or communicate via TCP/IP sockets in various protocols: FTP, HTTP, POP3, SMTP, IMAP, etc. In this case, setting a strict Medium Trust will cause a failure. This blog post discusses how to provide full trust to specific DLLs: Giving Full Trust to a DLL in ASP.NET 2.0 You may also set Full Trust for everything by editing your web.config. (Full Trust is the out-of-the-box default.)
This is the error message you would get if a DLL that requires full trust does not get it:
Server Error in '/' Application.
Required permissions cannot be acquired.
Description: An unhandled exception occurred during the execution of the current web request. Please review
the stack trace for more information about the error and where it originated in the code.
Exception Details: System.Security.Policy.PolicyException: Required permissions cannot be acquired.
Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding
the origin and location of the exception can be identified using the exception stack trace below.
Stack Trace:
[PolicyException: Required permissions cannot be acquired.]
System.Security.SecurityManager.ResolvePolicy(Evidence evidence, PermissionSet reqdPset,
PermissionSet optPset, PermissionSet denyPset, PermissionSet& denied, Boolean checkExecutionPermission)
+2796809
System.Security.SecurityManager.ResolvePolicy(Evidence evidence, PermissionSet reqdPset,
PermissionSet optPset, PermissionSet denyPset, PermissionSet& denied, Int32& securitySpecialFlags,
Boolean checkExecutionPermission) +57
[FileLoadException: Could not load file or assembly 'ChilkatDotNet2, Version=8.2.2.0, Culture=neutral,
PublicKeyToken=eb5fc1fc52ef09bd' or one of its dependencies. Failed to grant minimum permission requests.
(Exception from HRESULT: 0x80131417)]
System.Reflection.Assembly.nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity,
Assembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection) +0
System.Reflection.Assembly.InternalLoad(AssemblyName assemblyRef, Evidence assemblySecurity,
StackCrawlMark& stackMark, Boolean forIntrospection) +211
System.Reflection.Assembly.InternalLoad(String assemblyString, Evidence assemblySecurity,
StackCrawlMark& stackMark, Boolean forIntrospection) +141
System.Reflection.Assembly.Load(String assemblyString) +25
System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName,
Boolean starDirective) +32
[ConfigurationErrorsException: Could not load file or assembly 'ChilkatDotNet2, Version=8.2.2.0,
Culture=neutral, PublicKeyToken=eb5fc1fc52ef09bd' or one of its dependencies.
Failed to grant minimum permission requests. (Exception from HRESULT: 0x80131417)]
System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName,
Boolean starDirective) +596
System.Web.Configuration.CompilationSection.LoadAllAssembliesFromAppDomainBinDirectory() +3596761
System.Web.Configuration.CompilationSection.LoadAssembly(AssemblyInfo ai) +46
System.Web.Compilation.BuildManager.GetReferencedAssemblies(CompilationSection compConfig) +177
System.Web.Compilation.WebDirectoryBatchCompiler..ctor(VirtualDirectory vdir) +267
System.Web.Compilation.BuildManager.BatchCompileWebDirectoryInternal(VirtualDirectory vdir,
Boolean ignoreErrors) +36
System.Web.Compilation.BuildManager.BatchCompileWebDirectory(VirtualDirectory vdir,
VirtualPath virtualDir, Boolean ignoreErrors) +429
System.Web.Compilation.BuildManager.CompileWebFile(VirtualPath virtualPath) +73
System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath,
Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile) +580
System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context,
VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile) +93
System.Web.Compilation.BuildManager.GetVirtualPathObjectFactory(VirtualPath virtualPath,
HttpContext context, Boolean allowCrossApp, Boolean noAssert) +111
System.Web.Compilation.BuildManager.CreateInstanceFromVirtualPath(VirtualPath virtualPath,
Type requiredBaseType, HttpContext context, Boolean allowCrossApp, Boolean noAssert) +54
System.Web.UI.PageHandlerFactory.GetHandlerHelper(HttpContext context, String requestType,
VirtualPath virtualPath, String physicalPath) +31
System.Web.UI.PageHandlerFactory.GetHandler(HttpContext context, String requestType,
String virtualPath, String path) +37
System.Web.MaterializeHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +295
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155
Version Information: Microsoft .NET Framework Version:2.0.50727.312; ASP.NET Version:2.0.50727.833
