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Asked: 2020-01-12 05:11:40 +0800 CST 2020-01-12 05:11:40 +0800 CST

Error 'An object with the same key already exists in the ObjectStateManager'

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I have the following statements to Modify an Entity Framework object that is linked to an oracle database:

        using (BASEntities context = new BASEntities())
            {
        //Este método comprueba que exista en caso de existir modificar
        string RespuestaValidacion = ExisteConcepto(context, ConceptoTo);
             CONCEPTO objConceptoBasico = new  CONCEPTO
               {
                  CODIGOCTO = ConceptoTo.CodigoConcepto,
                  CODIGOENTIDAD = ConceptoTo.CodigoEntidad,
                   demas codigo..... 
                };

         if (string.IsNullOrEmpty(RespuestaValidacion))
                {
                    context.CONCEPTO.Add(objConceptoBasico);
                    context.SaveChanges();
                }
                else 
                {
                  context.CONCEPTO.Attach(objConceptoBasico);
                 context.CONCEPTO.System.Data.Entity.EntityState.Modified(objConceptoBasico);
                  context.SaveChanges();
                }

the method to Find if the record exists is as follows:

   private string ExisteConcepto(BASEntities context, ConceptoTO ConceptoTo)
    {
        try
        {
            var qRegistro = context.SMT_CONCEPTOBASICO.Where(k => 
                                    k.CODIGONEG == ConceptoTo.CodigoNegocio
                                    && k.CODIGOCTO == ConceptoTo.CodigoConcepto
                                    && k.IDAPLICACION == ConceptoTo.IdAplicacion
                                    demas codigo......).FirstOrDefault();                    


            return qRegistro == null ? "" : qRegistro.ESTADO;
        }
        catch (Exception error)
        {
            throw error;
        }
    }

And the mentioned error comes out:

Error 'An object with the same key already exists in the ObjectStateManager. The ObjectStateManager cannot track multiple objects with the same key.'

make the change from entity 5 to entity 6

c#

1 Answers

  1. Best Answer

    That is a bug caused by EF validations.

    To fix it you can do something like:

    try
{
  context.Configuration.ValidateOnSaveEnabled = false;

  context.CONCEPTO.Attach(objConceptoBasico);
  context.Entry(objConceptoBasico).State = EntityState.Deleted;
  context.SaveChanges();
}
finally
{
  context.Configuration.ValidateOnSaveEnabled = true;
}

    =================== EDITING =======================

    The error occurs because you are trying to add an entity that has already been implicitly added when performing the FirstOrDefaultin the: method ExisteConcepto.

    I know 2 ways to solve the same:

    1. You can in the method: ExisteConceptoreturn the object instead of string and change the properties of the object (if it exists) manually or with AupoMapper (for example).

    Something like:

    private string ExisteConcepto(BASEntities context, ConceptoTO ConceptoTo)
    {
        try
        {
            return context.SMT_CONCEPTOBASICO.Where(k => 
                                    k.CODIGONEG == ConceptoTo.CodigoNegocio
                                    && k.CODIGOCTO == ConceptoTo.CodigoConcepto
                                    && k.IDAPLICACION == ConceptoTo.IdAplicacion
                                    demas codigo......).FirstOrDefault();                    
        }
        catch (Exception error)
        {
            throw error;
        }
    }

    Then in your main method:

    ...
CONCEPTO concepto = ExisteConcepto(context, ConceptoTo);

if(concepto == null) concepto = new CONCEPTO();
...

    Then proceed to change the properties if the concept exists or add them if it is new:

    concepto.CODIGOCTO = ConceptoTo.CodigoConcepto;
...

    This is the way I personally recommend.

    1. The second way is to do a Countinstead of a FirstOrDefaultin the method: ExisteConceptothen you will return the number of elements that match the where criteria and in the main method you will only evaluate instead of: string.IsNullOrEmpty(RespuestaValidacion)something like:RespuestaValidacion == 0
    • 1