EntityFramework.dll中出现“System.Xml.XmlException”类型的异常，但未在用户代码中处理

Question

New to programming, new to stackoverflow, so apologies if this is not an appropriate question. I am getting a error message and I am completely dumbfounded as too what is wrong with my program.

Basically, whenever I try to call a view, I get the error as described in the title. Some examples of where my program is failing:

Line 22:         public ActionResult Index()
Line 23:         {
**Line 24:             return View(db.hostSystems.ToList());**
Line 25:         }
Line 26: 

Below is a different example:

Line 20:         public ActionResult Index()
Line 21:         {
**Line 22:             var hostDocuments = db.hostDocuments.Include(b => b.hostSystem);**
Line 23:             return View(hostDocuments.ToList());
Line 24:         }

This is happening on every single view. I have tried to scaffold a new instructor, but again, but the error occurs on any generated views.

I also get the same error when I try to run an update-database on the Package Management console:

PM> update-database -Force
Specify the '-Verbose' flag to view the SQL statements being applied to the target database.
Applying explicit migrations: [201610121010400_InitialCreate, 201610141128247_NewFields, 201610141215392_changes, 201610141223280_changes2].
Applying explicit migration: 201610121010400_InitialCreate.
System.Xml.XmlException: Syntax for an XML declaration is invalid. Line 1, position 21.
   at System.Xml.XmlTextReaderImpl.Throw(Exception e)
   at System.Xml.XmlTextReaderImpl.Throw(String res, String arg)
   at System.Xml.XmlTextReaderImpl.ParseXmlDeclaration(Boolean isTextDecl)
   at System.Xml.XmlTextReaderImpl.Read()
   at System.Xml.Linq.XDocument.Load(XmlReader reader, LoadOptions options)
   at System.Xml.Linq.XDocument.Load(Stream stream, LoadOptions options)
   at System.Data.Entity.Migrations.Edm.ModelCompressor.Decompress(Byte[] bytes)
   at System.Data.Entity.Migrations.DbMigration.GetModel(Func`2 modelAccessor)
   at System.Data.Entity.Migrations.DbMigration.GetTargetModel()
   at System.Data.Entity.Migrations.DbMigrator.ApplyMigration(DbMigration migration, DbMigration lastMigration)
   at System.Data.Entity.Migrations.Infrastructure.MigratorLoggingDecorator.ApplyMigration(DbMigration migration, DbMigration lastMigration)
   at System.Data.Entity.Migrations.DbMigrator.Upgrade(IEnumerable`1 pendingMigrations, String targetMigrationId, String lastMigrationId)
   at System.Data.Entity.Migrations.Infrastructure.MigratorLoggingDecorator.Upgrade(IEnumerable`1 pendingMigrations, String targetMigrationId, String lastMigrationId)
   at System.Data.Entity.Migrations.DbMigrator.UpdateInternal(String targetMigration)
   at System.Data.Entity.Migrations.DbMigrator.<>c__DisplayClassc.<Update>b__b()
   at System.Data.Entity.Migrations.DbMigrator.EnsureDatabaseExists(Action mustSucceedToKeepDatabase)
   at System.Data.Entity.Migrations.Infrastructure.MigratorBase.EnsureDatabaseExists(Action mustSucceedToKeepDatabase)
   at System.Data.Entity.Migrations.DbMigrator.Update(String targetMigration)
   at System.Data.Entity.Migrations.Infrastructure.MigratorBase.Update(String targetMigration)
   at System.Data.Entity.Migrations.Design.ToolingFacade.UpdateRunner.Run()
   at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate)
   at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate)
   at System.Data.Entity.Migrations.Design.ToolingFacade.Run(BaseRunner runner)
   at System.Data.Entity.Migrations.Design.ToolingFacade.Update(String targetMigration, Boolean force)
   at System.Data.Entity.Migrations.UpdateDatabaseCommand.<>c__DisplayClass2.<.ctor>b__0()
   at System.Data.Entity.Migrations.MigrationsDomainCommand.Execute(Action command)
Syntax for an XML declaration is invalid. Line 1, position 21.

Everything was working fine yesterday. I came in today and started to use my machine and have had this problem ever since. I am absolutely besides myself on what is wrong, and just can't understand why this is now occurring. Have checked many other threads that haven't helped.

Thank you for any assistance.

Answer 1

In the end it was due to a corrupted migration. I am still investigating the problem, but it is solved.

Thanks all