C# Execute PerformClick() on a Submit Button Not Firing

Epicor ERP 10
,
14 
private void txtLotNumScan_ValueChanged(object sender, System.EventArgs args)
	{
		// ** Place Event Handling Code Here **
		EpiTextBox partNum = (EpiTextBox)csm.GetNativeControlReference("52c8193e-d045-4605-b11f-85d0fe8b54a8");
		EpiTextBox lotNum = (EpiTextBox)csm.GetNativeControlReference("46567b2e-6bc0-4967-be35-a0ec6843838f");
		EpiTextBox tbxDescription = (EpiTextBox)csm.GetNativeControlReference("7c422ab4-6df2-4e5e-ad82-196021b36a2a");
		string scanLot = txtLotNumScan.Text.ToString();
		//MessageBox.Show(scanLot);
		if (scanLot != null)
		{
		//if using dynamic query...
		DynamicQueryAdapter qryPartLot = new DynamicQueryAdapter(oTrans); 
		QueryExecutionDataSet exDS = new QueryExecutionDataSet();
		QueryExecutionDataSet parameters = new QueryExecutionDataSet();
		
		DataRow paramRow = parameters.ExecutionParameter.NewRow();
		paramRow["ParameterID"] = "LotNum";
    	paramRow["ParameterValue"] = scanLot;		
    	paramRow["ValueType"] = "nvarchar(30)";
    	paramRow["IsEmpty"] = "False";
		parameters.ExecutionParameter.Rows.Add(paramRow);
			
		qryPartLot.BOConnect();
		qryPartLot.ExecuteByID("HH_ReturnPartNum", parameters);	
	    DataSet dsPartLot = qryPartLot.QueryResults;
		qryPartLot.Dispose();	
			
		foreach (DataRow dr in dsPartLot.Tables[0].Rows)
			{
			//MessageBox.Show(dr["PartLot_PartNum"].ToString());
			partNum.Value = dr["PartLot_PartNum"].ToString();				
			}	
		partNum.Focus();
		lotNum.Focus();
		lotNum.Value = scanLot;
		lotNum.Focus();
		tbxDescription.Focus();
		}

Example similar to yours, not using a button event but using textbox control events of the form.