我在C＃WPF应用程序中收到以下错误：
StackTrace " at System.Linq.Enumerable.Single[TSource](IEnumerable`1 source, Func`2 predicate)
at System.Data.Entity.Utilities.DbProviderManifestExtensions.GetStoreTypeFromName(DbProviderManifest providerManifest, String name)
at System.Data.Entity.ModelConfiguration.Configuration.Properties.Primitive.PrimitivePropertyConfiguration.ConfigureColumn(EdmProperty column, EntityType table, DbProviderManifest providerManifest)
at System.Data.Entity.ModelConfiguration.Configuration.Properties.Primitive.PrimitivePropertyConfiguration.Configure(EdmProperty column, EntityType table, DbProviderManifest providerManifest, Boolean allowOverride, Boolean fillFromExistingConfiguration)
at System.Data.Entity.ModelConfiguration.Configuration.Properties.Primitive.PrimitivePropertyConfiguration.<>c__DisplayClass4.<Configure>b__3(Tuple`2 pm)
at System.Data.Entity.Utilities.IEnumerableExtensions.Each[T](IEnumerable`1 ts, Action`1 action)
at System.Data.Entity.ModelConfiguration.Configuration.Properties.Primitive.PrimitivePropertyConfiguration.Configure(IEnumerable`1 propertyMappings, DbProviderManifest providerManifest, Boolean allowOverride, Boolean fillFromExistingConfiguration)
at System.Data.Entity.ModelConfiguration.Configuration.Types.StructuralTypeConfiguration.ConfigurePropertyMappings(IList`1 propertyMappings, DbProviderManifest providerManifest, Boolean allowOverride)
at System.Data.Entity.ModelConfiguration.Configuration.Types.EntityTypeConfiguration.ConfigurePropertyMappings(DbDatabaseMapping databaseMapping, EntityType entityType, DbProviderManifest providerManifest, Boolean allowOverride)
at System.Data.Entity.ModelConfiguration.Configuration.Types.EntityTypeConfiguration.Configure(EntityType entityType, DbDatabaseMapping databaseMapping, DbProviderManifest providerManifest)
at System.Data.Entity.ModelConfiguration.Configuration.ModelConfiguration.ConfigureEntityTypes(DbDatabaseMapping databaseMapping, ICollection`1 entitySets, DbProviderManifest providerManifest)
at System.Data.Entity.ModelConfiguration.Configuration.ModelConfiguration.Configure(DbDatabaseMapping databaseMapping, DbProviderManifest providerManifest)
at System.Data.Entity.DbModelBuilder.Build(DbProviderManifest providerManifest, DbProviderInfo providerInfo)
at System.Data.Entity.DbModelBuilder.Build(DbConnection providerConnection)
at System.Data.Entity.Internal.LazyInternalContext.CreateModel(LazyInternalContext internalContext)
at System.Data.Entity.Internal.RetryLazy`2.GetValue(TInput input)
at System.Data.Entity.Internal.LazyInternalContext.InitializeContext()
at System.Data.Entity.Internal.InternalContext.Initialize()
at System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType)
at System.Data.Entity.Internal.Linq.InternalSet`1.Initialize()
at System.Data.Entity.Internal.Linq.InternalSet`1.GetEnumerator()
at System.Data.Entity.Infrastructure.DbQuery`1.System.Collections.IEnumerable.GetEnumerator()
at System.Data.Entity.QueryableExtensions.Load(IQueryable source)
at Insurance_MidAm_Interface.MainWindow.Window_Loaded(Object sender, RoutedEventArgs e) in c:\\Users\\Khandokar\\Documents\\Visual Studio 2013\\Projects\\Insurance MidAm Interface\\Insurance MidAm Interface\\MainWindow.xaml.cs:line 80" string
这是抛出异常的代码：
System.Windows.Data.CollectionViewSource employeeViewSource = ((System.Windows.Data.CollectionViewSource)(this.FindResource("employeeViewSource")));
try { dbContext.employees.Load(); //// Line 80
}
catch (Exception EX)
{
Console.Write(EX.InnerException);
}
employeeViewSource.Source = dbContext.employees.ToList();
}
我几乎尝试了所有我能想到的东西。我已经将测试数据添加到数据库中，甚至放置了employeeViewSource.Source = dbContext.employees.ToList（）和dbContext.employees.Load（）;在Try / Catch块中。每当我执行后者时，应用程序将加载，但每当我尝试添加实体时，我都会得到相同的错误。我环顾四周，大多数解决方案都没有调用Single（而是使用SingleOrDefault）。但是，我没有明确地打电话给＆＃34; Single＆＃34; （虽然从Stack Trace看来，它显然已经被调用了。）
问题可能是什么？
非常感谢。
员工模型
public partial class employee
{
public employee()
{
beneficiaries = new HashSet<beneficiary>();
children = new HashSet<child>();
reports = new HashSet<report>();
spouses = new HashSet<spouse>();
visions = new HashSet<vision>();
}
[Key]
[Column(Order = 0)]
[StringLength(12)]
public string id { get; set; }
[Key]
[Column(Order = 1)]
[StringLength(4)]
public string year { get; set; }
[Required]
[StringLength(30)]
public string first { get; set; }
[Required]
[StringLength(30)]
public string last { get; set; }
[Required]
[StringLength(10)]
public string gender { get; set; }
[Required]
[StringLength(50)]
public string email { get; set; }
[Column(TypeName = "text")]
[Required]
public string address { get; set; }
[Required]
[StringLength(50)]
public string location { get; set; }
public DateTime birth { get; set; }
private string _displayDate;
public string displayDate
{
get
{
_displayDate = this.birth.ToShortDateString();
return _displayDate;
}
}
private string displaySSN;
public string SSN
{
get
{
ssnDecrypter decrypter = new ssnDecrypter();
decrypter.cryptString = this.ssn;
byte[] key = decrypter.hexToBin(MainWindow.KEY);
byte[] ssn = decrypter.hexToBin(decrypter.getSSN());
byte[] iv = decrypter.hexToBin(decrypter.getIV());
displaySSN = decrypter.decrypter(ssn, key, iv);
return displaySSN;
}
}
[StringLength(50)]
public string decision { get; set; }
[Required]
[StringLength(10)]
public string dependents { get; set; }
[Required]
[StringLength(30)]
public string vision { get; set; }
[Required]
public string ssn { get; set; }
public bool filed { get; set; }
public virtual ICollection<beneficiary> beneficiaries { get; set; }
public virtual ICollection<child> children { get; set; }
public virtual ICollection<report> reports { get; set; }
public virtual ICollection<spouse> spouses { get; set; }
public virtual ICollection<vision> visions { get; set; }
}
}
insuranceModel（dbContext）
public partial class insuranceModel : DbContext
{
public insuranceModel()
: base("name=insuranceModel2")
{
}
public virtual DbSet<action> actions { get; set; }
public virtual DbSet<beneficiary> beneficiaries { get; set; }
public virtual DbSet<child> children { get; set; }
public virtual DbSet<employee> employees { get; set; }
public virtual DbSet<report> reports { get; set; }
public virtual DbSet<spouse> spouses { get; set; }
public virtual DbSet<vision> visions { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<action>()
.HasMany(e => e.reports)
.WithRequired(e => e.action)
.HasForeignKey(e => e.decision)
.WillCascadeOnDelete(false);
modelBuilder.Entity<beneficiary>()
.Property(e => e.year)
.IsFixedLength()
.IsUnicode(false);
modelBuilder.Entity<beneficiary>()
.Property(e => e.ssn)
.IsUnicode(false);
modelBuilder.Entity<beneficiary>()
.Property(e => e.name)
.IsFixedLength();
modelBuilder.Entity<beneficiary>()
.Property(e => e.address)
.IsUnicode(false);
modelBuilder.Entity<child>()
.Property(e => e.year)
.IsFixedLength()
.IsUnicode(false);
modelBuilder.Entity<child>()
.Property(e => e.ssn)
.IsUnicode(false);
modelBuilder.Entity<employee>()
.Property(e => e.year)
.IsFixedLength()
.IsUnicode(false);
modelBuilder.Entity<employee>()
.Property(e => e.address)
.IsUnicode(false);
modelBuilder.Entity<employee>()
.Property(e => e.location)
.IsFixedLength();
modelBuilder.Entity<employee>()
.Property(e => e.ssn)
.IsUnicode(false);
modelBuilder.Entity<employee>()
.HasMany(e => e.beneficiaries)
.WithRequired(e => e.employee)
.HasForeignKey(e => new { e.empId, e.year })
.WillCascadeOnDelete(false);
modelBuilder.Entity<employee>()
.HasMany(e => e.children)
.WithRequired(e => e.employee)
.HasForeignKey(e => new { e.empId, e.year })
.WillCascadeOnDelete(false);
modelBuilder.Entity<employee>()
.HasMany(e => e.reports)
.WithRequired(e => e.employee)
.HasForeignKey(e => new { e.empId, e.year })
.WillCascadeOnDelete(false);
modelBuilder.Entity<employee>()
.HasMany(e => e.spouses)
.WithRequired(e => e.employee)
.HasForeignKey(e => new { e.empId, e.year })
.WillCascadeOnDelete(false);
modelBuilder.Entity<employee>()
.HasMany(e => e.visions)
.WithRequired(e => e.employee)
.HasForeignKey(e => new { e.empId, e.year })
.WillCascadeOnDelete(false);
modelBuilder.Entity<report>()
.Property(e => e.year)
.IsFixedLength()
.IsUnicode(false);
modelBuilder.Entity<spouse>()
.Property(e => e.year)
.IsFixedLength()
.IsUnicode(false);
modelBuilder.Entity<spouse>()
.Property(e => e.ssn)
.IsUnicode(false);
modelBuilder.Entity<spouse>()
.Property(e => e.name)
.IsUnicode(false);
modelBuilder.Entity<spouse>()
.Property(e => e.address)
.IsUnicode(false);
modelBuilder.Entity<spouse>()
.Property(e => e.gender)
.IsUnicode(false);
modelBuilder.Entity<spouse>()
.Property(e => e.isEmployed)
.IsUnicode(false);
modelBuilder.Entity<vision>()
.Property(e => e.year)
.IsFixedLength()
.IsUnicode(false);
modelBuilder.Entity<vision>()
.Property(e => e.ssn)
.IsUnicode(false);
modelBuilder.Entity<vision>()
.Property(e => e.name)
.IsUnicode(false);
modelBuilder.Entity<vision>()
.Property(e => e.gender)
.IsUnicode(false);
}
}
}