How to pass a query to CrystalReportViewer1.SelectionFormula

Dear All,

I have a problem to pass a query to  CrystalReportViewer.SelectionFormula.  Here is my query :           

             sParam = " {qryGLTRX.TrxDate} >= \'" + Convert.ToDateTime(sTGL1) + "\'";
             sParam = sParam + " and {qryGLTRX.TrxDate} <= " + "\'" + Convert.ToDateTime(sTGL2) + "\'";
             sParam = sParam + " and {qryGLTRX.Trxactno} >= " + "\'" + sCOA1 + "\'";
             sParam = sParam + " and {qryGLTRX.Trxactno} <= " + "\'" + sCOA2 + "\'";

I want to pass that query to CrystalReportViewer.SelectionFormula = sParam

CrystalReportViewer1.ReportSource = rptDoc;
CrystalReportViewer.SelectionFormula = sParam;
rptDoc.Refresh();

Is it possible to do this ?

I always get an error like this below

FormulaException was unhandled by user code

A date-time is required here.
Details: errorKind
Error in File ledger_card {553AD865-BB07-4ED3-AD49-8D36EEC3B4A5}.rpt:
Error in formula  Record_Selection: 
' {qryGLTRX.TrxDate} >= '4/1/2014 12:00:00 AM' and {qryGLTRX.TrxDate} <= '5/2/2014 12:00:00 AM' and {qryGLTRX.Trxactno} >= '20000000' and {qryGLTRX.Trxactno} <= '30000000''
A date-time is required here.
Details: errorKind

Does anyone know how to solve this problem ?

Regards,

Sentoso