Web API 2 - 用戶登錄失敗

Question

我是C＃和web api開發中的新手。在嘗試遵循大量教程之後，我一直未能將我的SQL Azure數據庫連接到Web API。對於重複性，這些是我所遵循的步驟：

1. 在Visual Studio
2. 創建新項目的ASP.NET Web應用程序中選擇「空模板」，並檢查網絡API箱
3. 安裝NuGet包：實體框架
4. 添加「字」模型作爲ADO.Net實體數據模型（然後從數據庫EF設計）
5. 配置我的服務器（SQL Server身份驗證和選擇，以避免暴露我的WebConfig密碼的選項），並在成功測試連接。然後在我的數據庫中選擇Word表格。與行動的Web API 2的Controler，使用實體框架
6. 生成解決方案
7. 新增模式：
8. 創建控制器。在嚮導中，選擇模型類和數據上下文以前創建
9. 重新生成並運行

然後我去http://localhost:XXXXX/api/words並不斷收到以下錯誤：

<Error> 
<Message>An error has occurred.</Message> 
<ExceptionMessage> 
The 'ObjectContent`1' type failed to serialize the response body for content type 'application/xml; charset=utf-8'. 
</ExceptionMessage> 
<ExceptionType>System.InvalidOperationException</ExceptionType> 
<StackTrace/> 
<InnerException> 
<Message>An error has occurred.</Message> 
<ExceptionMessage>The underlying provider failed on Open.</ExceptionMessage> 
<ExceptionType>System.Data.Entity.Core.EntityException</ExceptionType> 
<StackTrace> 
at System.Data.Entity.Core.EntityClient.EntityConnection.Open() at System.Data.Entity.Core.Objects.ObjectContext.EnsureConnection(Boolean shouldMonitorTransactions) at System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransaction[T](Func`1 func, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction, Boolean releaseConnectionOnSuccess) at System.Data.Entity.Core.Objects.ObjectQuery`1.<>c__DisplayClass7.<GetResults>b__5() at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func`1 operation) at System.Data.Entity.Core.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption) at System.Data.Entity.Core.Objects.ObjectQuery`1.<System.Collections.Generic.IEnumerable<T>.GetEnumerator>b__0() at System.Data.Entity.Internal.LazyEnumerator`1.MoveNext() at WriteArrayOfWordToXml(XmlWriterDelegator , Object , XmlObjectSerializerWriteContext , CollectionDataContract) at System.Runtime.Serialization.CollectionDataContract.WriteXmlValue(XmlWriterDelegator xmlWriter, Object obj, XmlObjectSerializerWriteContext context) at System.Runtime.Serialization.XmlObjectSerializerWriteContext.WriteDataContractValue(DataContract dataContract, XmlWriterDelegator xmlWriter, Object obj, RuntimeTypeHandle declaredTypeHandle) at System.Runtime.Serialization.XmlObjectSerializerWriteContext.SerializeWithoutXsiType(DataContract dataContract, XmlWriterDelegator xmlWriter, Object obj, RuntimeTypeHandle declaredTypeHandle) at System.Runtime.Serialization.DataContractSerializer.InternalWriteObjectContent(XmlWriterDelegator writer, Object graph, DataContractResolver dataContractResolver) at System.Runtime.Serialization.DataContractSerializer.InternalWriteObject(XmlWriterDelegator writer, Object graph, DataContractResolver dataContractResolver) at System.Runtime.Serialization.XmlObjectSerializer.WriteObjectHandleExceptions(XmlWriterDelegator writer, Object graph, DataContractResolver dataContractResolver) at System.Runtime.Serialization.DataContractSerializer.WriteObject(XmlWriter writer, Object graph) at System.Net.Http.Formatting.XmlMediaTypeFormatter.WriteToStream(Type type, Object value, Stream writeStream, HttpContent content) at System.Net.Http.Formatting.XmlMediaTypeFormatter.WriteToStreamAsync(Type type, Object value, Stream writeStream, HttpContent content, TransportContext transportContext, CancellationToken cancellationToken) --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at System.Web.Http.WebHost.HttpControllerHandler.<WriteBufferedResponseContentAsync>d__1b.MoveNext() 
</StackTrace> 
<InnerException> 
<Message>An error has occurred.</Message> 
<ExceptionMessage>Login failed for user [myUserName].</ExceptionMessage> 
<ExceptionType>System.Data.SqlClient.SqlException</ExceptionType> 
<StackTrace> 
at System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData, DbConnectionPool pool, String accessToken, Boolean applyTransientFaultHandling) at System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions) at System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions) at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) at System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection) at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection) at System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection) at System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions) at System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions) at System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource`1 retry) at System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry) at System.Data.SqlClient.SqlConnection.Open() at System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.<Open>b__36(DbConnection t, DbConnectionInterceptionContext c) at System.Data.Entity.Infrastructure.Interception.InternalDispatcher`1.Dispatch[TTarget,TInterceptionContext](TTarget target, Action`2 operation, TInterceptionContext interceptionContext, Action`3 executing, Action`3 executed) at System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.Open(DbConnection connection, DbInterceptionContext interceptionContext) at System.Data.Entity.Core.EntityClient.EntityConnection.<Open>b__2() at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.<>c__DisplayClass1.<Execute>b__0() at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func`1 operation) at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute(Action operation) at System.Data.Entity.Core.EntityClient.EntityConnection.Open() 
</StackTrace> 
</InnerException> 
</InnerException> 
</Error> 

Answer 1

報價：

「當涉及到從Web Api（或任何其他Web服務）返回數據給用戶時，我強烈建議不要傳回來自數據庫的實體。使用Models in的可靠性和可維護性要高得多您可以控制數據的外觀而不是數據庫。這樣您就不必在WebApiConfig中亂搞格式化程序。您可以創建一個具有子模型作爲屬性的UserModel，並擺脫返回對象中的引用循環。這使得序列化器更加快樂。

此外，如果您只是在請求中指定「接受」標頭，則通常不需要移除格式化程序或支持的媒體類型。玩弄的東西有時會令事情變得更加混亂「

請參閱：？ Failed to serialize the response in Web API with Json