Queries :: Run Saved Query Object In Access Through VBA And Display Result In Subform

I have saved query object named qrySearchBill. I wan to call this query through vba and display the result in a subform named subQrySearchBills in datasheet view. Here's how I want it to work:

When the main form loads, I want all unfiltered records to be displayed in the subform initially. The user may then decide to filter based on date range, so he enters startdate and enddate parameter values in their respective textboxes in the main form. Then click search button to run the saved query based on the date range parameter taken from the textboxes.

I have this code so far:

SQL of the saved query object:

Code:
PARAMETERS [StartDate] DateTime, [EndDate] DateTime;
SELECT tblInvoice.BillNo, tblCrdCustomer.CstName, tblCrdCustomer.CstAddress, tblCrdCustomer.Island, tblInvoice.Date, Sum(tblInvoice.[TotalPrice]) AS Amount
FROM tblCrdCustomer INNER JOIN tblInvoice ON tblCrdCustomer.IDNo = tblInvoice.NameID
WHERE tblInvoice.Date Between [StartDate] And [EndDate]
GROUP BY tblInvoice.BillNo, tblCrdCustomer.CstName, tblCrdCustomer.CstAddress, tblCrdCustomer.Island, tblInvoice.Date;

vba code to call the query and its parameter:

Private Sub btnSearchBill_Click()
Dim qdf As DAO.QueryDef
Dim rst As DAO.Recordset

Set qdf = CurrentDb.QueryDefs("qrySearchBills")

[Code] ...

This code works fine except that when the main form loads, a prompt window appears to ask for the value of dateStart and dateEnd. I don't want it to prompt because it's suppose to get these values from the main form's textboxes (txtStartDate and txtEndDate respectively), plus it should initially display all the unfiltered records.