problem dropdownlist filtering a list box

Question

4.00/5 (1 vote)

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When something is selected in a DropDownList, I want this to change what is displayed in a ListBox.

I would like to make something the same as this:
Example
Please see the "Filter" DropDownList which changes the data in the ListBox below it.

What is the easiest way to do this using ASP.NET and VB?
is there any tutorial regarding this?
I created a code but so far no good.
It only shows the first default text of the dropdown and when you choose another text the list box when blank

VB

Dim strSQL As String
Dim connection As SqlConnection = New SqlConnection("Data Source=ML0003135586;Initial Catalog=TestSQL;Integrated Security=True")
strSQL = "SELECT [CourseTitle] FROM [tblTrainingPlan] WHERE ([Category] LIKE '%' + @Category + '%')"
connection.Open()

Dim command As New SqlCommand(strSQL, connection)
command.Parameters.AddWithValue("@Category", ddcategory.SelectedValue)
cbTitle.DataSource = command.ExecuteReader
cbTitle.DataTextField = "CourseTitle"
cbTitle.DataValueField = "CourseTitle"
cbTitle.DataBind()
command.Dispose()
connection.Close()

Posted 16-May-11 14:32pm

janwel

Updated 16-May-11 14:55pm

v2

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Comments

walterhevedeich 16-May-11 20:49pm

what do you mean so far no good? are there any errors? or does it behave correctly? elaborate your scenario.

janwel 16-May-11 20:53pm

Sir it only post the first text on the dropdownlist and when I hit second text of the dropdown, the data of the list box went all blank(white)

saxenaabhi6 16-May-11 21:31pm

show the code of onclick event of your dropdown

janwel 16-May-11 21:38pm

sir i only add text from smart tags which is the same as the category in database

janwel 16-May-11 21:56pm

sir the the error

2 solutions

Solution 2

XML

<asp:DropDownList ID="ddcategory" runat="server" Height="27px" Width="293px" AutoPostBack="True">
    <asp:ListItem Value="4">Fluor University Functional Courses (instructor-led)</asp:ListItem>
    <asp:ListItem Value="1">GEE 51 Bulletin Requirements</asp:ListItem>
    <asp:ListItem Value="2">Cross Functional Courses</asp:ListItem>
    <asp:ListItem Value="3">Functional Courses (online)</asp:ListItem>
    <asp:ListItem Value="5">Local Functional Courses (instructor-led)</asp:ListItem>
    <asp:ListItem Value="6">External Courses</asp:ListItem>
    <asp:ListItem Value="7">Other Courses</asp:ListItem>
    <asp:ListItem></asp:ListItem>
</asp:DropDownList></div>

Sir this is my code on dropdownlist . there is no click event

Posted 16-May-11 15:47pm

janwel

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saxenaabhi6 · Accepted Answer · 2011-05-16T15:29:00

Solution 1

if on server side:

1. load the dropdown on page load inside the if condition of 'not postback' (we discussed it before in your previous questions)
2. load and bind the listbox on the click event of dropdown

if on client side (i.e in javascript)
read this

Posted 16-May-11 15:29pm

saxenaabhi6

Updated 16-May-11 15:31pm

v2

Comments

janwel 16-May-11 21:55pm

sir found the error ^^ thanks anyway