vb.net - Trying to get a data from sql database: what to enter into textbox -

i have text-box named txtitemcode, when type item-code text box want to display corresponding data grid-view or text boxes.

but it's not firing code, don't know wrong, search in google , keep change codes , got 1 still not working. pasting code here..

public sub selectitem(byval itemcode string)         try             sql.opendbconnection()             dim strsql string = "select itemcode 'item code',itemname 'item name' tblitemmaster itemcode='itemcode'"             'sqlconn.close()             dim da new sqldataadapter(strsql, sql.sqlconn)             dim ds new dataset             da.fill(ds, "tblitemmaster")             dgvpurchaseorder.datasource = ds.tables("tblitemmaster")             sql.sqlconn.close()         catch ex sqlexception             msgbox(ex.message, msgboxstyle.critical, "sql error")         catch ex exception             msgbox(ex.message, msgboxstyle.critical, "general error")         end try     end sub 

i call class text lostfocus, click , of doubted events, no luck ..

you not passing parameter correctly. try this:

dim strsql string = "select itemcode 'item code',itemname 'item name' " & _     " tblitemmaster itemcode= @itemcode" dim cmd new sqlcommand(strsql, sql.sqlconn) dim ds new dataset  cmd.parameters.addwithvalue("itemcode", itemcode)  dim da new sqldataadapter(cmd) da.fill(ds, "tblitemmaster") 

take @ msdn documentation it.