asp.net - Adding Session Variable as OleDbParameter - running into error " -

i using custom asp.net control found here: http://www.codeproject.com/articles/5347/datacalendar

i have used 1 of templates in source file download-able page above starting point custom calendar. aim display events current user has created. doing creating session variable called "username" , parameterizing in query so:

function geteventdata(startdate datetime, enddate datetime) datatable     '--read data access query     dim con oledbconnection = getconnection()     dim cmd oledbcommand = new oledbcommand()     cmd.connection = con     cmd.parameters.addwithvalue("@currentuser", session("currentuser"))     cmd.commandtext = string.format("select eventdate, createdby, count(*) eventinfo (createdby = @currentuser) , eventdate >= #{0}# , eventdate <= #{1}# group eventdate", _                                     startdate, enddate)     dim ds dataset = new dataset()     dim da oledbdataadapter = new oledbdataadapter(cmd)     da.fill(ds)     con.close()     return ds.tables(0) end function 

unfortunately receiving error:

parameter[0] '' has no default value. 

i have ensured logged in not problem of there being no value user.identity.name (i don't think). creating session variable in page load sub:

sub page_load(o object, e eventargs)         session("currentuser") = user.identity.name     end sub 

so, what's going wrong?

from msdn :

the ole db.net provider not support named parameters passing parameters sql statement or stored procedure called oledbcommand when commandtype set text. in case, question mark (?) placeholder must used. example:

select * customers customerid = ? 

therefore, order in oledbparameter objects added oledbparametercollection must directly correspond position of question mark placeholder parameter.

try:

cmd.commandtext = string.format("select eventdate, createdby, count(*) eventinfo ([createdby = ?]) , eventdate >= #{0}# , eventdate <= #{1}# group eventdate,createdby", startdate, enddate)