entity-framework

问题 I have the following record set ID BatchID ClientName CreatedDateTime ----------- -------------- --------------- ----------------------- 1 NULL B 2018-02-16 19:07:46.320 2 NULL B 2018-02-16 19:07:46.320 3 NULL B 2018-02-16 19:07:46.597 4 NULL B 2018-02-16 19:07:46.597 5 NULL B 2018-02-16 19:10:10.260 6 NULL B 2018-02-16 19:10:10.260 7 NULL B 2018-02-16 19:21:34.303 8 NULL B 2018-02-16 19:21:34.303 9 NULL B 2018-02-16 19:21:44.780 10 NULL B 2018-02-16 19:21:44.780 11 NULL A 2018-02-16 19:24:35

问题 As Title showed, When I use lazyload of Entity Framework 4.1 which turned tracking off I got the error. Complete exception message: When an object is returned with a NoTracking merge option, Load can only be called when the EntityCollection or EntityReference does not contain objects Does anyone knows why? 回答1: Set the Configuration.ProxyCreationEnabled field of your DbContext to false : using (var dbContext = MyDbContext()) { dbContext.Configuration.ProxyCreationEnabled = false; return

问题 As Title showed, When I use lazyload of Entity Framework 4.1 which turned tracking off I got the error. Complete exception message: When an object is returned with a NoTracking merge option, Load can only be called when the EntityCollection or EntityReference does not contain objects Does anyone knows why? 回答1: Set the Configuration.ProxyCreationEnabled field of your DbContext to false : using (var dbContext = MyDbContext()) { dbContext.Configuration.ProxyCreationEnabled = false; return

问题 Example of entities: public class HistoryWorkoutExercise : EntityMaximum { /// <summary> /// Gets or sets the Weight. /// </summary> public decimal? Weight { get; set; } /// <summary> /// Gets or sets the Speed. /// </summary> public decimal? Speed { get; set; } /// <summary> /// Gets or sets the Time. /// </summary> public decimal? Time { get; set; } public int NumberOfRepetitions { get; set; } public int NumberOfCompletedRepetitions { get; set; } public int ExerciseId { get; set; } public

问题 Example of entities: public class HistoryWorkoutExercise : EntityMaximum { /// <summary> /// Gets or sets the Weight. /// </summary> public decimal? Weight { get; set; } /// <summary> /// Gets or sets the Speed. /// </summary> public decimal? Speed { get; set; } /// <summary> /// Gets or sets the Time. /// </summary> public decimal? Time { get; set; } public int NumberOfRepetitions { get; set; } public int NumberOfCompletedRepetitions { get; set; } public int ExerciseId { get; set; } public

问题 I have the following entities: public abstract class Freezer { public int FreezerId { get; set; } public string Name { get; set; } public int FreezerTypeId { get; set; } public int Capacity { get; set; } } public class FoodFreezer : Freezer { public List<FoodItem> Foods { get; set; } } public class ChemicalFreezer : Freezer { public List<ChemicalItem> Chemicals { get; set; } } As you can see the derived Freezer classes do not contain any data that would be stored in the database; they only

问题 I have the following entities: public abstract class Freezer { public int FreezerId { get; set; } public string Name { get; set; } public int FreezerTypeId { get; set; } public int Capacity { get; set; } } public class FoodFreezer : Freezer { public List<FoodItem> Foods { get; set; } } public class ChemicalFreezer : Freezer { public List<ChemicalItem> Chemicals { get; set; } } As you can see the derived Freezer classes do not contain any data that would be stored in the database; they only

问题 Background: I have 200+ legacy VB6 apps which I am converting to C#, using EntityFramework Core as our ORM. Unfortunately a lot of the apps utilize MySQL's zero date (0000-00-00) . So I need to cater for this and be able to store a zero date in some way. Changing the fundamental way this works in the 200+ apps is not currently an option. Setup: I can define an entity property which represents the field definition in MySQL eg: public DateTime ExpiryDate { get; set; } ... entity.Property(e => e

问题 In my code there are transactions to handle: using (var scope = new TransactionScope()) { repo1.SaveSomething(); repo2.SaveAnythingElse(); scope.Complete(); } Inside repo1 and repo2 functions create their own db context with using, and dispose them, the transactions worked like a charm. Now I add another code like this, and it begins to drop an exception: The underlying provider failed on Open. (EntityFramework) Network access for Distributed Transaction Manager (MSDTC) has been disabled.

问题 I am developing winform application using entityframework in visual studio 2012 with database first approach. Suddenly I am facing the following error:- The model backing the 'POSContext' context has changed since the database was created. Consider using Code First Migrations to update the database (http://go.microsoft.com/fwlink/?LinkId=238269). Can any please immediately help me to resolve this issue. I shall be very thankful for timely help. Thanks. 回答1: make sure that you don't have a