When I try to reference the lstproducts.selecteditem.value using
autopostback from the lstproducts listbox I get an error? How can I
fix my code to get the selected value from the lstproducts listbox?
Any help will be appreciated.
Sincerely,
Allan
error code:
===============================================
Server Error in '/' Application.
--------------------------------------------
Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of
the current web request. Please review the stack trace for more
information about the error and where it originated in the code.
Exception Details: System.NullReferenceException: Object reference not
set to an instance of an object.
Source Error:
Line 75: response.write(lstproducts.selecteditem.value +
" ")
============================================
source code:
===========================================
<%@ Page Language="VB" debug="true"%>
<%@ import Namespace="system.data.sqlclient" %>
<script runat="server">
' Insert page code here
'
dim strbg as string="white"
sub page_load
dim strOrderBy as string
if not ispostback then
strOrderBy = "SSN"
else
if radSSN.checked then
strOrderBy = "SSN"
else
strOrderBy = "Name"
end if
end if
dim conMyData as sqlconnection
dim cmdSelect as sqlcommand
dim dtrNames as sqldatareader
conMyData = new
sqlconnection("server=xxxxxxxx;uid=xxxxxx;pwd=xxxx x;database=xxxxxx")
conMyData.open()
if strOrderBy = "SSN" then
cmdSelect = new sqlcommand("select ssn + ' | ' +
lname + ', ' + fname as person, ssn from EEHIST where deleted = 0
order by SSN", conMyData)
lblHeader.text = "Find Employee By SSN"
else
cmdSelect = new sqlcommand("select ssn + ' | ' +
lname + ', ' + fname as person, ssn from EEHIST where deleted = 0
order by lname", conMyData)
lblHeader.text = "Find Employee By Name"
end if
dtrNames = cmdSelect.ExecuteReader()
lstProducts.datasource = dtrNames
lstProducts.datatextfield = "person"
lstProducts.datavaluefield = "ssn"
lstProducts.databind()
dtrNames.close()
conMyData.close()
end sub
sub lstproducts_selectedindexchanged(s as object, e as
eventargs)
response.write(lstproducts.selecteditem.value + " ")
response.write("emps_person_plan.aspx")
end sub
sub lstcolors_selectedindexchanged(s as object, e as eventargs)
response.write(lstcolors.selecteditem.value + " ")
strbg = lstcolors.selecteditem.value
if strbg <> "white" then
response.write("not white")
end if
'response.redirect("emps.aspx")
end sub
</script>
<html>
<head>
</head>
<body bgcolor="<%=strbg%>">
<form runat="server">
<asp:listbox id="lstcolors" autopostback="true"
onselectedindexchanged="lstcolors_selectedindexcha nged"
runat="server">
<asp:listitem text="select one" value="white" selected="true"/>
<asp:listitem text="red" value="red"/>
<asp:listitem text="green" value="green"/>
<asp:listitem text="blue" value="blue"/>
</asp:listbox>
<asp:radiobutton id="radSSN" checked="true" groupname="orderby"
autopostback="true" text="By SSN" runat="server"/>
<asp:radiobutton id="radName" groupname="orderby" autopostback="true"
text="By Name" runat="server"/>
<asp:label id="lblHeader" runat="server"/>
<asp:listbox id="lstproducts"
onselectedindexchanged="lstproducts_selectedindexc hanged"
autopostback="true" rows="10" font-size="14px"
runat="server"/>
</form>
</body>
</html>
=================================================
