Multiple Select List

[rn5a]

A Form has 2 select lists. The 1st one whose size is 5 (meaning 5
options are shown at any given time) allows multiple selection whereas
the 2nd one allows only 1 option to be selected at a time.

When an option is selected in the 2nd select list, the ASP page posts
itself. Assume that the 1st select list has the following 10 options
(note that both the select lists are actually populated from 2
different database tables):

Australia
Brazil
Canada
Denmark
Egypt
Finland
Ghana
Holland
India
Japan

Suppose a user has selected Brazil, Finland & Holland in the 1st
select list. Next the user selects an option in the 2nd select list.
This causes the ASP page to post. Now after posting the page, I want
the 1st select list to maintain its state so that Brazil, Finland &
Holland remain selected (since the user had selected these 3 options
in the 1st select list just before the page posted). This is how I
tried it but it selects only the last option among the 3 options (i.e.
after the page posts, only Holland remains selected):

===================================
<%
Dim arrLID,iEachLID,iLID,strLID,selFlag

strLID=Request.Form("location")

Dim objConn
Set objConn=Server.CreateObject("ADODB.CONNECTION")
'open the connection using ConnectionString

Dim strSQL
strSQL="SELECT * FROM Locations"

Dim objRS
Set objRS=Server.CreateObject("ADODB.RECORDSET")
objRS.Open strSQL,objConn
%>
<select name="location" multiple size=5>
<%
Do Until(objRS.EOF)
If Not(IsEmpty(strLID)) Then
arrLID=Split(strLID,", ")
For Each iEachLID In arrLID
iLID=iEachLID
If(CInt(iLID)=CInt(objRS("LID"))) Then
selFlag=" selected"
Else
selFlag=""
End If
Next
Else
selFlag=""
End If
%>
<option value="<%= objRS("LID") %>"<%= selFlag %>><%=
objRS("Location") %></option>
<%
objRS.MoveNext
Loop
%>
</select>
===================================

Can someone please point out what am I missing in the above code?

 

[Bob Barrows [MVP]]

A Form has 2 select lists. The 1st one whose size is 5 (meaning 5
options are shown at any given time) allows multiple selection whereas
the 2nd one allows only 1 option to be selected at a time.

When an option is selected in the 2nd select list, the ASP page posts
itself. Assume that the 1st select list has the following 10 options
(note that both the select lists are actually populated from 2
different database tables):

Australia
Brazil
Canada
Denmark
Egypt
Finland
Ghana
Holland
India
Japan

Suppose a user has selected Brazil, Finland & Holland in the 1st
select list. Next the user selects an option in the 2nd select list.
This causes the ASP page to post. Now after posting the page, I want
the 1st select list to maintain its state so that Brazil, Finland &
Holland remain selected (since the user had selected these 3 options
in the 1st select list just before the page posted). This is how I
tried it but it selects only the last option among the 3 options (i.e.
after the page posts, only Holland remains selected):

===================================
<%
Dim arrLID,iEachLID,iLID,strLID,selFlag

strLID=Request.Form("location")

Dim objConn
Set objConn=Server.CreateObject("ADODB.CONNECTION")
'open the connection using ConnectionString

Dim strSQL
strSQL="SELECT * FROM Locations" http://www.aspfaq.com/show.asp?id=2096

Dim objRS
Set objRS=Server.CreateObject("ADODB.RECORDSET")
objRS.Open strSQL,objConn
%>
<select name="location" multiple size=5>
<%
Do Until(objRS.EOF)
If Not(IsEmpty(strLID)) Then
arrLID=Split(strLID,", ")
For Each iEachLID In arrLID
iLID=iEachLID
If(CInt(iLID)=CInt(objRS("LID"))) Then
selFlag=" selected"
Else
selFlag=""
End If
Next

OK, the arrLID array contains Brazil, Finland and Holland. Walk through the
code. The first recordset item I assume is Australia (despite the lack of an
Order By clause on your query - you should not depend on the order of the
results without an Order By clause). None of the array items match, so
Australia remains unselected. Now Brazil gets tested. Brazil == Brazil, so
selFlag is set to "selected". Ah! but the loop is not finished! It now
compares Brazil to Finland, and, since they are not equal, it sets selFlag
back to ""!

The solution is simple, you need to break out of the For loop when a match
is found. Do this by adding Exit For immediately after setting selFlag to
"selected"

You may want to consider a more efficient solution:

Dim arrLID,iEachLID,iLID,strLID,selFlag
Dim arData, i, sLocation

strLID=Request.Form("location")

'Split this string ONCE, outside of the loop
If Not(IsEmpty(strLID)) Then
arrLID=Split(strLID,", ")
End IF

strSQL="SELECT LID,Location FROM Locations Order By LID"
Set objRS= objConn.Execute(strSQL,,1) '1=adCmdText
If Not objRS.EOF then arData = objRS.GetRows
objRS.Close:Set objRS=Nothing
'if you are done with the connection, close and destroy
'it here as well

if IsArray(arData) then
for i = 0 to ubound(arData,2)
iLID = CInt(arData(0,i)) 'if LID is int in the db Cint is not
needed
sLocation = arData(1,i)
selFlag = ""
if isArray(arrLID) then
for each iEachLID in arLID
if CInt(iEachLID) = iLID then
selFlag="selected"
exit for
end if
next 'iEachLID
end if
%>
<option value="<%= iLID%>"<%= selFlag %>><%=
sLocation%></option>

<%
next 'i
end if

 

[rn5a]

OK, the arrLID array contains Brazil, Finland and Holland. Walk through the
code. The first recordset item I assume is Australia (despite the lack of an
Order By clause on your query - you should not depend on the order of the
results without an Order By clause). None of the array items match, so
Australia remains unselected. Now Brazil gets tested. Brazil == Brazil, so
selFlag is set to "selected". Ah! but the loop is not finished! It now
compares Brazil to Finland, and, since they are not equal, it sets selFlag
back to ""!

The solution is simple, you need to break out of the For loop when a match
is found. Do this by adding Exit For immediately after setting selFlag to
"selected"

You may want to consider a more efficient solution:

Dim arrLID,iEachLID,iLID,strLID,selFlag
Dim arData, i, sLocation

strLID=Request.Form("location")

'Split this string ONCE, outside of the loop
If Not(IsEmpty(strLID)) Then
arrLID=Split(strLID,", ")
End IF

strSQL="SELECT LID,Location FROM Locations Order By LID"
Set objRS= objConn.Execute(strSQL,,1) '1=adCmdText
If Not objRS.EOF then arData = objRS.GetRows
objRS.Close:Set objRS=Nothing
'if you are done with the connection, close and destroy
'it here as well

if IsArray(arData) then
for i = 0 to ubound(arData,2)
iLID = CInt(arData(0,i)) 'if LID is int in the db Cint is not
needed
sLocation = arData(1,i)
selFlag = ""
if isArray(arrLID) then
for each iEachLID in arLID
if CInt(iEachLID) = iLID then
selFlag="selected"
exit for
end if
next 'iEachLID
end if
%>
<option value="<%= iLID%>"<%= selFlag %>><%=
sLocation%></option>

<%
next 'i
end if

--
Microsoft MVP - ASP/ASP.NET
Please reply to the newsgroup. This email account is my spam trap so I
don't check it very often. If you must reply off-line, then remove the
"NO SPAM"- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

Bob, it was indeed very very kind of you to show a more efficient way
to do the same thing. Thanks a lot.

Regards,

RON

 

[rn5a]

Bob, it was indeed very very kind of you to show a more efficient way
to do the same thing. Thanks a lot.

Regards,

RON- Hide quoted text -

- Show quoted text -

Bob, I encountered a new problem with the 1st select list.

Suppose Brazil, Finland & Holland are selected in the 1st select list.
Next I select an option from the 2nd select list; the page posts & the
1st select list shows Brazil, Finland & Holland selected.

After this, I again select a different option in the 2nd select list;
again the page gets posted but surprisingly, the options selected in
the 1st select list i.e. Brazil, Finland & Holland no longer remain
selected. In fact, when I click the submit button, the action page
just retrieves an empty string i.e. Request.Form("location") is just
an empty string instead of the location ids (objRS("LID")) of the 3
locations!

Why is the 1st select list losing its state under such circumstances?

Please note that when an option is selected in the 2nd selected list,
the page posts to itself (which I have done using JavaScript) but when
the submit button is clicked, the page posts to another page.

 

[Bob Barrows [MVP]]

Bob, I encountered a new problem with the 1st select list.

Suppose Brazil, Finland & Holland are selected in the 1st select list.
Next I select an option from the 2nd select list; the page posts & the
1st select list shows Brazil, Finland & Holland selected.

After this, I again select a different option in the 2nd select list;
again the page gets posted but surprisingly, the options selected in
the 1st select list i.e. Brazil, Finland & Holland no longer remain
selected. In fact, when I click the submit button, the action page
just retrieves an empty string i.e. Request.Form("location") is just
an empty string instead of the location ids (objRS("LID")) of the 3
locations!

Why is the 1st select list losing its state under such circumstances?

Please note that when an option is selected in the 2nd selected list,
the page posts to itself (which I have done using JavaScript) but when
the submit button is clicked, the page posts to another page.

It's got to have something to do with the way the form is getting submitted.
Help us out by posting a small repro. Create a new pair of test pages that
contain nothing but the code needed to reproduce this problem and post them
here. We need to run your code in order to test it, and we do not have your
database, so hardcode the option list in the second select element and
substitute an ad hoc recordset for the recordset actually used in your
actual code to populate the first select element:

Dim objRS
const adInteger=3
const adVarChar = 200
Set objRS = createobject("adodb.recordset")
With objRS.Fields
.Append "LID",adInteger
.Append "Location",adVarChar,100
End With
objRS.Open
With objRS
.AddNew Array("LID","Location"), Array(1,"Australia")
.AddNew Array("LID","Location"), Array(2,"Brazil")
'etc.
End With


The second test page will likely contain only this code:
<%
Response.Write "Request.Form(""location"") contains """ & _
Request.Form("location")