EF 5.0 Error while calling save changes multiple times in a single context call

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entity-framework

Error: The changes to the database were committed successfully, but an error occurred while updating the object context. The ObjectContext might be in an inconsistent state. Inner exception message: AcceptChanges cannot continue because the object's key values conflict with another object in the ObjectStateManager. Make sure that the key values are unique before calling AcceptChanges.


The below mentioned code runs successfully when used without stored procedures but fails on using stored procedures for saving and updating the user entity.

public string Index()
        {
            string s = "";

            //EFWithoutSP context = new EFWithoutSP();
            EFWithSP context = new EFWithSP();
            try
            {
                context.Configuration.AutoDetectChangesEnabled = false;

                User user01 = new User()
                {
                    FirstName = "abhi" + DateTime.Now.ToString("yyyyMMddhhmmss"),
                    LastName = "mith" + DateTime.Now.ToString("yyyyMMddhhmmss"),
                };
                Console.WriteLine("adding user {0},{1}", user01.LastName, user01.FirstName);
                context.Users.Add(user01);
                //context.Entry(user01).State = System.Data.EntityState.Added;
                context.ChangeTracker.DetectChanges();
                context.SaveChanges();
                s += DisplayEntityInfo(user01, "added user01");

                Thread.Sleep(1000);
                

                User user02 = new User()
                {
                    FirstName = "abhi" + DateTime.Now.ToString("yyyyMMddhhmmss"),
                    LastName = "mith" + DateTime.Now.ToString("yyyyMMddhhmmss"),
                };
                Console.WriteLine("adding user {0},{1}", user02.LastName, user02.FirstName);
                context.Users.Add(user02);
                //context.Entry(user02).State = System.Data.EntityState.Added;
                context.ChangeTracker.DetectChanges();
                context.SaveChanges();
                s += DisplayEntityInfo(user02, "added user02");


                User aUser01 = context.Users.First(u => u.FirstName == user01.FirstName);
                User bUser01 = context.Users.First(u => u.FirstName == user01.FirstName);

                if (aUser01 != null)
                {
                    aUser01.FirstName = "01" + aUser01.FirstName;
                }
                //context.Entry(aUser01).State = System.Data.EntityState.Modified;
                context.ChangeTracker.DetectChanges();
                context.SaveChanges();
                s += DisplayEntityInfo(aUser01, "updated aUser01");




                if (bUser01 != null)
                {
                    bUser01.FirstName = "02" + aUser01.FirstName;
                }
                //context.Entry(bUser01).State = System.Data.EntityState.Modified;
                context.ChangeTracker.DetectChanges();
                context.SaveChanges();
                s += DisplayEntityInfo(bUser01, "updated bUser01");

            }
            catch (Exception ex)
            {
                s += ex.Message;
                if (null != ex.InnerException)
                    s += ex.InnerException.Message;
            }
            return s;
        }

        private string DisplayEntityInfo(User user, string note)
        {
            return string.Format("{0} ||| {1} ||| {2}<br>", user.GetHashCode(), user.UserID, note);
        }

sql code

/****** Object:  Table [dbo].[UsersAuditLog]    Script Date: 03/05/2014 19:08:31 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[UsersAuditLog](
	[ID] [bigint] IDENTITY(1,1) NOT NULL PRIMARY KEY,
	[UserID] [int] NOT NULL,
	[FirstName] [nvarchar](50) NOT NULL,
	[LastName] [nvarchar](50) NOT NULL
) ON [PRIMARY]
GO

/****** Object:  Table [dbo].[Users]    Script Date: 03/05/2014 19:08:31 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[Users](
	[UserID] [int] IDENTITY(1,1) NOT NULL PRIMARY KEY,
	[FirstName] [nvarchar](50) NOT NULL,
	[LastName] [nvarchar](50) NOT NULL,
	[Timestamp] [timestamp] NOT NULL
) ON [PRIMARY]
GO

/****** Object:  StoredProcedure [dbo].[UserUpdate]    Script Date: 03/05/2014 19:08:40 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE PROCEDURE [dbo].[UserUpdate]
	@UserID int,
	@FirstName nvarchar(50),
	@LastName nvarchar(50),	
	@Timestamp timestamp
AS
BEGIN

	SET NOCOUNT ON;
	
	BEGIN TRY
		IF NOT EXISTS(SELECT 1 FROM dbo.Users where UserID = @UserID AND [Timestamp] = @Timestamp)
		BEGIN
			UPDATE 
				dbo.Users
			SET
				FirstName = @FirstName, 
				LastName = @LastName
			WHERE
				UserID = @UserID				
		END
		ELSE
		BEGIN
			declare @errormsg varchar(max)
			select @errormsg = 'Record for user ' + @FirstName + ' ' + @LastName + ' modified by other user. Please select the record again.'
			RAISERROR (@errormsg, 16, 1)
		END
	END TRY
	BEGIN CATCH
		declare @ErMessage varchar(max)
		declare @ErSeverity int
		declare @ErState int
		
		SELECT
			@ErMessage = ERROR_MESSAGE(),
			@ErSeverity = 17,--ERROR_SEVERITY(),
			@ErState = ERROR_STATE()
 
		RAISERROR (@ErMessage, @ErSeverity, @ErState)
	END CATCH
	
	SELECT * FROM dbo.Users where UserID = @UserID
END
GO
/****** Object:  StoredProcedure [dbo].[UserDelete]    Script Date: 03/05/2014 19:08:40 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE PROCEDURE [dbo].[UserDelete]
	@UserID int
AS
BEGIN
	
	SET NOCOUNT ON;

    DELETE FROM dbo.Users where UserID = @UserID
    
END
GO
/****** Object:  StoredProcedure [dbo].[UserAdd]    Script Date: 03/05/2014 19:08:40 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE PROCEDURE [dbo].[UserAdd]
	@FirstName nvarchar(50),
	@LastName nvarchar(50)
AS
BEGIN

	declare @UserID int
	
	SET NOCOUNT ON;
	
	BEGIN TRY
		IF NOT EXISTS(SELECT 1 FROM dbo.Users where FirstName = @FirstName)
		BEGIN
			INSERT INTO dbo.Users(FirstName, LastName)
			VALUES (@FirstName, @LastName)
			
			SELECT 
				@UserID = SCOPE_IDENTITY()		
		END
		ELSE
		BEGIN
			declare @errormsg varchar(max)
			select @errormsg = 'FirstName ' + @FirstName + ' already exists. Please select a different username.'
			RAISERROR (@errormsg, 16, 1)
		END
	END TRY
	BEGIN CATCH
		declare @ErMessage varchar(max)
		declare @ErSeverity int
		declare @ErState int
		
		SELECT
			@ErMessage = ERROR_MESSAGE(),
			@ErSeverity = ERROR_SEVERITY(),
			@ErState = ERROR_STATE()
 
		RAISERROR (@ErMessage, @ErSeverity, @ErState)
	END CATCH
	
	SELECT * FROM dbo.Users WHERE UserID = @UserID
END
GO
/****** Object:  Trigger [TUserDelete]    Script Date: 03/05/2014 19:08:40 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TRIGGER [dbo].[TUserDelete]
   ON  [dbo].[Users]
   INSTEAD OF DELETE
AS 
BEGIN
	
	SET NOCOUNT ON;

    UPDATE 
		dbo.Users
	SET
		FirstName = FirstName -- basically do not delete, do nothing
	WHERE
		UserID = (select UserID from deleted)
END
GO
/****** Object:  Trigger [TUserAddUpdate]    Script Date: 03/05/2014 19:08:40 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TRIGGER [dbo].[TUserAddUpdate]
   ON  [dbo].[Users]
   AFTER INSERT,UPDATE
AS 
BEGIN
	
	SET NOCOUNT ON;

	INSERT INTO dbo.UsersAuditLog(UserID, FirstName, LastName)
	SELECT 
		UserID, FirstName, LastName
	FROM 
		inserted

END
GO