entity framework - The value can not be null.

I have this error
The value can not be null.
Parameter name: key
view attached EFerror

I am using visual studio 2008
actividadEDM.jpg
EFerror.jpg
EF01.jpg
enrique_aeoAsked:
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Jens FiedererTest Developer/ValidatorCommented:
Does "actividad" have a non-null EntityKey?
0
enrique_aeoAuthor Commented:
which verify that?
0
Jens FiedererTest Developer/ValidatorCommented:
Put a breakpoint on the line of code where it reads
      db.GetObjectByKey(actividad.EntityKey)

when the breakpoint is hit, use QuickWatch to inspect "actividad".

See if EntityKey was set.
0
enrique_aeoAuthor Commented:
it does not. View file
this is the code the table

CREATE TABLE [certifica].[Actividad](
      [Codigo] [int] IDENTITY(1,1) NOT NULL,
      [CodigoActividad] [bigint] NOT NULL,
      [NombreActividad] [varchar](200) NULL,
      [NombreSede] [varchar](50) NULL,
      [FechaInicio] [varchar](50) NULL,
      [FechaFin] [varchar](50) NULL,
      [DirigidoA] [varchar](200) NULL,
      [NombrePrograma] [varchar](200) NULL,
      [NumeroResolucion] [varchar](100) NULL,
      [HorasLectivas] [varchar](5) NULL,
PRIMARY KEY CLUSTERED
(
      [CodigoActividad] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]
enitysetKEYname.jpg
0
Jens FiedererTest Developer/ValidatorCommented:
Could you use CreateEntityKey before making the call like in

http://msdn.microsoft.com/en-us/library/dd283138.aspx
0

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