Hi Antonio,

>Hi all,
>
>I have an MM .NET 3.5 Entity with some fields. I need one of them to be updated from the value of two others, a division. I have created this code:
>

>	public partial class MuestrasEntity : ABusinessEntity
>	{
>		/// <summary>
>		/// MuestrasPK
>		/// </summary>
>		public int MuestrasPK
>		{
>			get
>			{
>				if (this.Row != null)
>					return (int)mmType.GetNonNullableDbValue(this.Row["MuestrasPK"], "System.Int32");
>				else
>					return this._muestrasPK;
>			}
>			set
>			{
>				if (this.Row != null)
>					this.Row["MuestrasPK"] = value; 
>				this._muestrasPK = value;
>				this.OnPropertyChanged(new PropertyChangedEventArgs("MuestrasPK"));
>			}
>		}
>		private int _muestrasPK;
>
>		/// <summary>
>		/// ValorTotal
>		/// </summary>
>		public decimal ValorTotal
>		{
>			get
>			{
>				if (this.Row != null)
>					return (decimal)mmType.GetNonNullableDbValue(this.Row["ValorTotal"], "System.Decimal");
>				else
>					return this._valorTotal;
>			}
>			set
>			{
>				if (this.Row != null)
>					this.Row["ValorTotal"] = value; 
>				this._valorTotal = value;
>				this.OnPropertyChanged(new PropertyChangedEventArgs("ValorTotal"));
>                this.SetValorUnitario();
>			}
>		}
>		private decimal _valorTotal;
>
>		/// <summary>
>		/// Superficie
>		/// </summary>
>		public Single Superficie
>		{
>			get
>			{
>				if (this.Row != null)
>					return (Single)mmType.GetNonNullableDbValue(this.Row["Superficie"], "System.Single");
>				else
>					return this._superficie;
>			}
>			set
>			{
>				if (this.Row != null)
>					this.Row["Superficie"] = value; 
>				this._superficie = value;
>				this.OnPropertyChanged(new PropertyChangedEventArgs("Superficie"));
>                                                                                      this.SetValorUnitario();
>			}
>		}
>		private Single _superficie;
>
>		/// <summary>
>		/// ValorUnitario
>		/// </summary>
>		public decimal ValorUnitario
>		{
>			get
>			{
>				if (this.Row != null)
>					return (decimal)mmType.GetNonNullableDbValue(this.Row["ValorUnitario"], "System.Decimal");
>				else
>					return this._valorUnitario;
>			}
>			set
>			{
>				if (this.Row != null)
>					this.Row["ValorUnitario"] = value; 
>				this._valorUnitario = value;
>				this.OnPropertyChanged(new PropertyChangedEventArgs("ValorUnitario"));
>                                                                                     this.SetValorHomogeneo();
>			}
>		}
>		private decimal _valorUnitario;
>
>                                           private void SetValorUnitario()
>                                           {
>                                                      if (this.Superficie != 0) this.ValorUnitario = this.ValorTotal / (decimal)this.Superficie;
>                                           }
>
>                }
>
>

>
>I have created a SetValorUnitario Method in the entity class in order to make a division whenever the two other two fields are updated, and added the method after the onPropertyChanged() method.
>
>I feel that I can do it using events properly.
>
>Is there any proper way to do this?
>
>Thanks in advance

Other ideas to consider. You could add a validate method that does this and also verifes the two fields involved for proper values. If rules are not an issue and the two fields would always be valid, then you could add to the PreSave Hook method.
Tim