Azure 应用服务（移动）上的数据库上下文失败
Db context on azure app service (mobile) fails
我在 Azure App Service - Mobile 上有一个控制器 运行。跟踪显示以下代码运行良好，直到 db.SaveChanges() 失败。
var telemetry = new Microsoft.ApplicationInsights.TelemetryClient();
telemetry.TrackTrace("Create User");
using (BCMobileAppContext db = new BCMobileAppContext())
{
string Username_NoSpaces = username.Username.Replace(" ", "");
var user = db.Users.FirstOrDefault(u => u.Username_NoSpaces == Username_NoSpaces || u.MicrosoftToken == this.User.Identity.Name);
telemetry.TrackTrace("1");
if (user == null && !Username_NoSpaces.Contains(","))
{
telemetry.TrackTrace("2");
DateTime now = DateTime.UtcNow;
telemetry.TrackTrace("3");
string username_noSpaces = username.Username.Replace(" ", "");
DataObjects.User userItem = new DataObjects.User() { Created = now, UserId = this.User.Identity.Name, MicrosoftToken = this.User.Identity.Name, Username_NoSpaces = username_noSpaces, Update = now, Username = username.Username, Gold = 1, Level = 1, Title = "Sir", InGameCrest = "", ReceiveNotifications = true };
telemetry.TrackTrace("4");
UserDTO returnObject1 = new UserDTO() { Created = userItem.Created, isCreated = true, MicrosoftId = userItem.MicrosoftToken, Username = userItem.Username };
telemetry.TrackTrace("5");
db.Users.Add(userItem);
telemetry.TrackTrace("6");
db.SaveChanges(); //Trace and code fails
telemetry.TrackTrace("7");
UserDTO returnObject = new UserDTO() { Created = userItem.Created, isCreated = true, MicrosoftId = userItem.MicrosoftToken, Username = userItem.Username };
telemetry.TrackTrace("8");
return Ok(returnObject);
}
}
来自应用服务诊断的堆栈跟踪（不幸的是我不明白）给出：
2016-04-07T17:29:19 PID[5008] Error Operation=ReflectedHttpActionDescriptor.ExecuteAsync, Exception=System.Data.Entity.Validation.DbEntityValidationException: Validation failed for one or more entities. See 'EntityValidationErrors' property for more details.
at System.Data.Entity.Internal.InternalContext.SaveChanges()
at System.Data.Entity.Internal.LazyInternalContext.SaveChanges()
at System.Data.Entity.DbContext.SaveChanges()
at BCMobileAppService.Controllers.Test2Controller.Post(UserDTO username) in C:\Users\johann\Desktop\BCMobileApp_Runtime\BCMobileAppService\Controllers\TestController.cs:line 78
at lambda_method(Closure , Object , Object[] )
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.<>c__DisplayClass10.<GetExecutor>b__9(Object instance, Object[] methodParameters)
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.Execute(Object instance, Object[] arguments)
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ExecuteAsync(HttpControllerContext controllerContext, IDictionary 2 arguments, 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.Web.Http.Tracing.ITraceWriterExtensions.<TraceBeginEndAsyncCore>d__18 1.MoveNext()
2016-04-07T17:29:19 PID[5008] Error Operation=ApiControllerActionInvoker.InvokeActionAsync, Exception=System.Data.Entity.Validation.DbEntityValidationException: Validation failed for one or more entities. See 'EntityValidationErrors' property for more details.
at System.Data.Entity.Internal.InternalContext.SaveChanges()
at System.Data.Entity.Internal.LazyInternalContext.SaveChanges()
at System.Data.Entity.DbContext.SaveChanges()
at BCMobileAppService.Controllers.Test2Controller.Post(UserDTO username) in C:\Users\johann\Desktop\BCMobileApp_Runtime\BCMobileAppService\Controllers\TestController.cs:line 78
at lambda_method(Closure , Object , Object[] )
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.<>c__DisplayClass10.<GetExecutor>b__9(Object instance, Object[] methodParameters)
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.Execute(Object instance, Object[] arguments)
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ExecuteAsync(HttpControllerContext controllerContext, IDictionary 2 arguments, 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.Web.Http.Tracing.ITraceWriterExtensions.<TraceBeginEndAsyncCore>d__18 1.MoveNext()
--- 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.Web.Http.Controllers.ApiControllerActionInvoker.<InvokeActionAsyncCore>d__0.MoveNext()
--- 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.Web.Http.Tracing.ITraceWriterExtensions.<TraceBeginEndAsyncCore>d__18 1.MoveNext()
2016-04-07T17:29:19 PID[5008] Error Operation=Test2Controller.ExecuteAsync, Exception=System.Data.Entity.Validation.DbEntityValidationException: Validation failed for one or more entities. See 'EntityValidationErrors' property for more details.
at System.Data.Entity.Internal.InternalContext.SaveChanges()
at System.Data.Entity.Internal.LazyInternalContext.SaveChanges()
at System.Data.Entity.DbContext.SaveChanges()
at BCMobileAppService.Controllers.Test2Controller.Post(UserDTO username) in C:\Users\johann\Desktop\BCMobileApp_Runtime\BCMobileAppService\Controllers\TestController.cs:line 78
at lambda_method(Closure , Object , Object[] )
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.< >c__DisplayClass10.<GetExecutor>b__9(Object instance, Object[] methodParameters)
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.Execute(Object instance, Object[] arguments)
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ExecuteAsync(HttpControllerContext controllerContext, IDictionary 2 arguments, 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.Web.Http.Tracing.ITraceWriterExtensions.<TraceBeginEndAsyncCore>d__18 1.MoveNext()
--- 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.Web.Http.Controllers.ApiControllerActionInvoker.<InvokeActionAsyncCore>d__0.MoveNext()
--- 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.Web.Http.Tracing.ITraceWriterExtensions.<TraceBeginEndAsyncCore>d__18 1.MoveNext()
--- 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.Web.Http.Filters.ActionFilterAttribute.<CallOnActionExecutedAsync>d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Web.Http.Filters.ActionFilterAttribute.<CallOnActionExecutedAsync>d__5.MoveNext()
--- 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.Web.Http.Filters.ActionFilterAttribute.<ExecuteActionFilterAsyncCore>d__0.MoveNext()
--- 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.Web.Http.Controllers.ActionFilterResult.<ExecuteAsync>d__2.MoveNext()
--- 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.Web.Http.Tracing.Tracers.HttpControllerTracer.<ExecuteAsyncCore>d__5.MoveNext()
--- 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.Web.Http.Tracing.ITraceWriterExtensions.<TraceBeginEndAsyncCore>d__18 1.MoveNext()
更新
所以我将尝试 this，这将提供更详细的错误消息：
catch (DbEntityValidationException dbEx)
{
foreach (var validationErrors in dbEx.EntityValidationErrors)
{
foreach (var validationError in validationErrors.ValidationErrors)
{
Trace.TraceInformation("Property: {0} Error: {1}",
validationError.PropertyName,
validationError.ErrorMessage);
}
}
}
还有
我将仔细检查所有设置，以确保根据 this answer on Whosebug.
，不能是 null 的字段是 null
测试以上内容
异常隐藏 Id 字段是必需的，是异常。
我的数据库使用 EntityData（描述为 here on msdn），其中 Id 来自。我在 MobileService 上的使用是 Id 是在我执行该行时创建的，它失败了 db.SaveChanges()。有人可以澄清一下吗？
class 看起来像这样：
public abstract class EntityData : ITableData
{
protected EntityData();
[Index(IsClustered = true)]
[TableColumn(TableColumnType.CreatedAt)]
public DateTimeOffset? CreatedAt { get; set; }
[TableColumn(TableColumnType.Deleted)]
public bool Deleted { get; set; }
[TableColumn(TableColumnType.Id)]
public string Id { get; set; }
[TableColumn(TableColumnType.UpdatedAt)]
public DateTimeOffset? UpdatedAt { get; set; }
[TableColumn(TableColumnType.Version)]
public byte[] Version { get; set; }
}
EF 不支持自动生成字符串主键。这就是为什么您应该手动分配主键。
您可以使用构造函数初始化 Id、CreatedDate 和 UpdatedDate。
public abstract class EntityData : ITableData
{
//Change the constructor to initilaize required filled with meaningful data.
protected EntityData()
{
Id=Guid.NewGuid().ToString();
CreatedDate=DateTime.UtcNow;
UpdatedDate=DateTime.UtcNow;
}
[Index(IsClustered = true)]
[TableColumn(TableColumnType.CreatedAt)]
public DateTimeOffset? CreatedAt { get; set; }
[TableColumn(TableColumnType.Deleted)]
public bool Deleted { get; set; }
[TableColumn(TableColumnType.Id)]
public string Id { get; set; }
[TableColumn(TableColumnType.UpdatedAt)]
public DateTimeOffset? UpdatedAt { get; set; }
[TableColumn(TableColumnType.Version)]
public byte[] Version { get; set; }
}
您可以在上下文中重写 savechanges 方法。当您修改实体时，此方法将自动更改更新日期。
public override int SaveChanges()
{
//Get Modified Entities
var modifiedEntries = ChangeTracker.Entries()
.Where(x => x.Entity is ITableData
&& (x.State == EntityState.EntityState.Modified));
foreach (var entry in modifiedEntries)
{
var entity = entry.Entity as ITableData;
//Modify updateddate
if (entity != null)
{
entity.UpdatedDate = DateTime.UtcNow;
}
}
return base.SaveChanges();
}
编辑：第一个解决方案是通用解决方案，未与任何库一起使用。
EntityData 您需要序列化。当移动客户端和后端服务器试图相互通信时，这个 class 会帮助你。例如，移动客户端不支持导航属性，但后端服务器支持。当您序列化实体数据时，它会为您隐藏这些属性。
如果您为此应用设计数据库。关注这个 document.
首先：你应该使用库中的EntityData Class。你的模型应该继承它而不是你的 EntityData Class.
其次：您的上下文应该包含此代码来覆盖模型创建。您需要这个来自动更新 created/updated at 和 Id（这是您问题的答案）。
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
string schema = ServiceSettingsDictionary.GetSchemaName();
if (!string.IsNullOrEmpty(schema))
{
modelBuilder.HasDefaultSchema(schema);
}
modelBuilder.Conventions.Add(
new AttributeToColumnAnnotationConvention<TableColumnAttribute, string>(
"ServiceTableColumn", (property, attributes) => attributes.Single().ColumnType.ToString()));
}
如果您使用已经存在的数据库，请遵循此 document。
我在 Azure App Service - Mobile 上有一个控制器 运行。跟踪显示以下代码运行良好，直到 db.SaveChanges() 失败。
var telemetry = new Microsoft.ApplicationInsights.TelemetryClient();
telemetry.TrackTrace("Create User");
using (BCMobileAppContext db = new BCMobileAppContext())
{
string Username_NoSpaces = username.Username.Replace(" ", "");
var user = db.Users.FirstOrDefault(u => u.Username_NoSpaces == Username_NoSpaces || u.MicrosoftToken == this.User.Identity.Name);
telemetry.TrackTrace("1");
if (user == null && !Username_NoSpaces.Contains(","))
{
telemetry.TrackTrace("2");
DateTime now = DateTime.UtcNow;
telemetry.TrackTrace("3");
string username_noSpaces = username.Username.Replace(" ", "");
DataObjects.User userItem = new DataObjects.User() { Created = now, UserId = this.User.Identity.Name, MicrosoftToken = this.User.Identity.Name, Username_NoSpaces = username_noSpaces, Update = now, Username = username.Username, Gold = 1, Level = 1, Title = "Sir", InGameCrest = "", ReceiveNotifications = true };
telemetry.TrackTrace("4");
UserDTO returnObject1 = new UserDTO() { Created = userItem.Created, isCreated = true, MicrosoftId = userItem.MicrosoftToken, Username = userItem.Username };
telemetry.TrackTrace("5");
db.Users.Add(userItem);
telemetry.TrackTrace("6");
db.SaveChanges(); //Trace and code fails
telemetry.TrackTrace("7");
UserDTO returnObject = new UserDTO() { Created = userItem.Created, isCreated = true, MicrosoftId = userItem.MicrosoftToken, Username = userItem.Username };
telemetry.TrackTrace("8");
return Ok(returnObject);
}
}
来自应用服务诊断的堆栈跟踪（不幸的是我不明白）给出：
2016-04-07T17:29:19 PID[5008] Error Operation=ReflectedHttpActionDescriptor.ExecuteAsync, Exception=System.Data.Entity.Validation.DbEntityValidationException: Validation failed for one or more entities. See 'EntityValidationErrors' property for more details.
at System.Data.Entity.Internal.InternalContext.SaveChanges()
at System.Data.Entity.Internal.LazyInternalContext.SaveChanges()
at System.Data.Entity.DbContext.SaveChanges()
at BCMobileAppService.Controllers.Test2Controller.Post(UserDTO username) in C:\Users\johann\Desktop\BCMobileApp_Runtime\BCMobileAppService\Controllers\TestController.cs:line 78
at lambda_method(Closure , Object , Object[] )
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.<>c__DisplayClass10.<GetExecutor>b__9(Object instance, Object[] methodParameters)
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.Execute(Object instance, Object[] arguments)
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ExecuteAsync(HttpControllerContext controllerContext, IDictionary 2 arguments, 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.Web.Http.Tracing.ITraceWriterExtensions.<TraceBeginEndAsyncCore>d__18 1.MoveNext()
2016-04-07T17:29:19 PID[5008] Error Operation=ApiControllerActionInvoker.InvokeActionAsync, Exception=System.Data.Entity.Validation.DbEntityValidationException: Validation failed for one or more entities. See 'EntityValidationErrors' property for more details.
at System.Data.Entity.Internal.InternalContext.SaveChanges()
at System.Data.Entity.Internal.LazyInternalContext.SaveChanges()
at System.Data.Entity.DbContext.SaveChanges()
at BCMobileAppService.Controllers.Test2Controller.Post(UserDTO username) in C:\Users\johann\Desktop\BCMobileApp_Runtime\BCMobileAppService\Controllers\TestController.cs:line 78
at lambda_method(Closure , Object , Object[] )
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.<>c__DisplayClass10.<GetExecutor>b__9(Object instance, Object[] methodParameters)
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.Execute(Object instance, Object[] arguments)
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ExecuteAsync(HttpControllerContext controllerContext, IDictionary 2 arguments, 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.Web.Http.Tracing.ITraceWriterExtensions.<TraceBeginEndAsyncCore>d__18 1.MoveNext()
--- 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.Web.Http.Controllers.ApiControllerActionInvoker.<InvokeActionAsyncCore>d__0.MoveNext()
--- 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.Web.Http.Tracing.ITraceWriterExtensions.<TraceBeginEndAsyncCore>d__18 1.MoveNext()
2016-04-07T17:29:19 PID[5008] Error Operation=Test2Controller.ExecuteAsync, Exception=System.Data.Entity.Validation.DbEntityValidationException: Validation failed for one or more entities. See 'EntityValidationErrors' property for more details.
at System.Data.Entity.Internal.InternalContext.SaveChanges()
at System.Data.Entity.Internal.LazyInternalContext.SaveChanges()
at System.Data.Entity.DbContext.SaveChanges()
at BCMobileAppService.Controllers.Test2Controller.Post(UserDTO username) in C:\Users\johann\Desktop\BCMobileApp_Runtime\BCMobileAppService\Controllers\TestController.cs:line 78
at lambda_method(Closure , Object , Object[] )
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.< >c__DisplayClass10.<GetExecutor>b__9(Object instance, Object[] methodParameters)
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.Execute(Object instance, Object[] arguments)
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ExecuteAsync(HttpControllerContext controllerContext, IDictionary 2 arguments, 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.Web.Http.Tracing.ITraceWriterExtensions.<TraceBeginEndAsyncCore>d__18 1.MoveNext()
--- 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.Web.Http.Controllers.ApiControllerActionInvoker.<InvokeActionAsyncCore>d__0.MoveNext()
--- 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.Web.Http.Tracing.ITraceWriterExtensions.<TraceBeginEndAsyncCore>d__18 1.MoveNext()
--- 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.Web.Http.Filters.ActionFilterAttribute.<CallOnActionExecutedAsync>d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Web.Http.Filters.ActionFilterAttribute.<CallOnActionExecutedAsync>d__5.MoveNext()
--- 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.Web.Http.Filters.ActionFilterAttribute.<ExecuteActionFilterAsyncCore>d__0.MoveNext()
--- 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.Web.Http.Controllers.ActionFilterResult.<ExecuteAsync>d__2.MoveNext()
--- 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.Web.Http.Tracing.Tracers.HttpControllerTracer.<ExecuteAsyncCore>d__5.MoveNext()
--- 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.Web.Http.Tracing.ITraceWriterExtensions.<TraceBeginEndAsyncCore>d__18 1.MoveNext()
更新
所以我将尝试 this，这将提供更详细的错误消息：
catch (DbEntityValidationException dbEx)
{
foreach (var validationErrors in dbEx.EntityValidationErrors)
{
foreach (var validationError in validationErrors.ValidationErrors)
{
Trace.TraceInformation("Property: {0} Error: {1}",
validationError.PropertyName,
validationError.ErrorMessage);
}
}
}
还有
我将仔细检查所有设置，以确保根据 this answer on Whosebug.
，不能是null 的字段是 null
测试以上内容
异常隐藏 Id 字段是必需的，是异常。
我的数据库使用 EntityData（描述为 here on msdn），其中 Id 来自。我在 MobileService 上的使用是 Id 是在我执行该行时创建的，它失败了 db.SaveChanges()。有人可以澄清一下吗？
class 看起来像这样：
public abstract class EntityData : ITableData
{
protected EntityData();
[Index(IsClustered = true)]
[TableColumn(TableColumnType.CreatedAt)]
public DateTimeOffset? CreatedAt { get; set; }
[TableColumn(TableColumnType.Deleted)]
public bool Deleted { get; set; }
[TableColumn(TableColumnType.Id)]
public string Id { get; set; }
[TableColumn(TableColumnType.UpdatedAt)]
public DateTimeOffset? UpdatedAt { get; set; }
[TableColumn(TableColumnType.Version)]
public byte[] Version { get; set; }
}
EF 不支持自动生成字符串主键。这就是为什么您应该手动分配主键。
您可以使用构造函数初始化 Id、CreatedDate 和 UpdatedDate。
public abstract class EntityData : ITableData
{
//Change the constructor to initilaize required filled with meaningful data.
protected EntityData()
{
Id=Guid.NewGuid().ToString();
CreatedDate=DateTime.UtcNow;
UpdatedDate=DateTime.UtcNow;
}
[Index(IsClustered = true)]
[TableColumn(TableColumnType.CreatedAt)]
public DateTimeOffset? CreatedAt { get; set; }
[TableColumn(TableColumnType.Deleted)]
public bool Deleted { get; set; }
[TableColumn(TableColumnType.Id)]
public string Id { get; set; }
[TableColumn(TableColumnType.UpdatedAt)]
public DateTimeOffset? UpdatedAt { get; set; }
[TableColumn(TableColumnType.Version)]
public byte[] Version { get; set; }
}
您可以在上下文中重写 savechanges 方法。当您修改实体时，此方法将自动更改更新日期。
public override int SaveChanges()
{
//Get Modified Entities
var modifiedEntries = ChangeTracker.Entries()
.Where(x => x.Entity is ITableData
&& (x.State == EntityState.EntityState.Modified));
foreach (var entry in modifiedEntries)
{
var entity = entry.Entity as ITableData;
//Modify updateddate
if (entity != null)
{
entity.UpdatedDate = DateTime.UtcNow;
}
}
return base.SaveChanges();
}
编辑：第一个解决方案是通用解决方案，未与任何库一起使用。
EntityData 您需要序列化。当移动客户端和后端服务器试图相互通信时，这个 class 会帮助你。例如，移动客户端不支持导航属性，但后端服务器支持。当您序列化实体数据时，它会为您隐藏这些属性。
如果您为此应用设计数据库。关注这个 document.
首先：你应该使用库中的EntityData Class。你的模型应该继承它而不是你的 EntityData Class.
其次：您的上下文应该包含此代码来覆盖模型创建。您需要这个来自动更新 created/updated at 和 Id（这是您问题的答案）。
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
string schema = ServiceSettingsDictionary.GetSchemaName();
if (!string.IsNullOrEmpty(schema))
{
modelBuilder.HasDefaultSchema(schema);
}
modelBuilder.Conventions.Add(
new AttributeToColumnAnnotationConvention<TableColumnAttribute, string>(
"ServiceTableColumn", (property, attributes) => attributes.Single().ColumnType.ToString()));
}
如果您使用已经存在的数据库，请遵循此 document。