public Int16 AgentNumber { get { if (this.Row != null) return (Int16)mmType.GetNonNullableDbValue(this.Row["AgentNumber"], "System.Int16"); else return this._agentNumber; } set { if (this.Row != null) this.Row["AgentNumber"] = value; this._agentNumber = value; this.OnPropertyChanged(new PropertyChangedEventArgs("AgentNumber")); } } private Int16 _agentNumber;The error occurs on this.Row["AgentNumber"] = value;